diff options
Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 2685 |
1 files changed, 2685 insertions, 0 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c new file mode 100644 index 00000000..0cb86ceb --- /dev/null +++ b/net/ipv4/tcp_ipv4.c @@ -0,0 +1,2685 @@ +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * Implementation of the Transmission Control Protocol(TCP). + * + * IPv4 specific functions + * + * + * code split from: + * linux/ipv4/tcp.c + * linux/ipv4/tcp_input.c + * linux/ipv4/tcp_output.c + * + * See tcp.c for author information + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +/* + * Changes: + * David S. Miller : New socket lookup architecture. + * This code is dedicated to John Dyson. + * David S. Miller : Change semantics of established hash, + * half is devoted to TIME_WAIT sockets + * and the rest go in the other half. + * Andi Kleen : Add support for syncookies and fixed + * some bugs: ip options weren't passed to + * the TCP layer, missed a check for an + * ACK bit. + * Andi Kleen : Implemented fast path mtu discovery. + * Fixed many serious bugs in the + * request_sock handling and moved + * most of it into the af independent code. + * Added tail drop and some other bugfixes. + * Added new listen semantics. + * Mike McLagan : Routing by source + * Juan Jose Ciarlante: ip_dynaddr bits + * Andi Kleen: various fixes. + * Vitaly E. Lavrov : Transparent proxy revived after year + * coma. + * Andi Kleen : Fix new listen. + * Andi Kleen : Fix accept error reporting. + * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which + * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind + * a single port at the same time. + */ + +#define pr_fmt(fmt) "TCP: " fmt + +#include <linux/bottom_half.h> +#include <linux/types.h> +#include <linux/fcntl.h> +#include <linux/module.h> +#include <linux/random.h> +#include <linux/cache.h> +#include <linux/jhash.h> +#include <linux/init.h> +#include <linux/times.h> +#include <linux/slab.h> + +#include <net/net_namespace.h> +#include <net/icmp.h> +#include <net/inet_hashtables.h> +#include <net/tcp.h> +#include <net/transp_v6.h> +#include <net/ipv6.h> +#include <net/inet_common.h> +#include <net/timewait_sock.h> +#include <net/xfrm.h> +#include <net/netdma.h> +#include <net/secure_seq.h> +#include <net/tcp_memcontrol.h> + +#include <linux/inet.h> +#include <linux/ipv6.h> +#include <linux/stddef.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> + +#include <linux/crypto.h> +#include <linux/scatterlist.h> + +int sysctl_tcp_tw_reuse __read_mostly; +int sysctl_tcp_low_latency __read_mostly; +EXPORT_SYMBOL(sysctl_tcp_low_latency); + + +#ifdef CONFIG_TCP_MD5SIG +static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, + __be32 daddr, __be32 saddr, const struct tcphdr *th); +#endif + +struct inet_hashinfo tcp_hashinfo; +EXPORT_SYMBOL(tcp_hashinfo); + +static inline __u32 tcp_v4_init_sequence(const struct sk_buff *skb) +{ + return secure_tcp_sequence_number(ip_hdr(skb)->daddr, + ip_hdr(skb)->saddr, + tcp_hdr(skb)->dest, + tcp_hdr(skb)->source); +} + +int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) +{ + const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw); + struct tcp_sock *tp = tcp_sk(sk); + + /* With PAWS, it is safe from the viewpoint + of data integrity. Even without PAWS it is safe provided sequence + spaces do not overlap i.e. at data rates <= 80Mbit/sec. + + Actually, the idea is close to VJ's one, only timestamp cache is + held not per host, but per port pair and TW bucket is used as state + holder. + + If TW bucket has been already destroyed we fall back to VJ's scheme + and use initial timestamp retrieved from peer table. + */ + if (tcptw->tw_ts_recent_stamp && + (twp == NULL || (sysctl_tcp_tw_reuse && + get_seconds() - tcptw->tw_ts_recent_stamp > 1))) { + tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2; + if (tp->write_seq == 0) + tp->write_seq = 1; + tp->rx_opt.ts_recent = tcptw->tw_ts_recent; + tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp; + sock_hold(sktw); + return 1; + } + + return 0; +} +EXPORT_SYMBOL_GPL(tcp_twsk_unique); + +/* This will initiate an outgoing connection. */ +int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) +{ + struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; + struct inet_sock *inet = inet_sk(sk); + struct tcp_sock *tp = tcp_sk(sk); + __be16 orig_sport, orig_dport; + __be32 daddr, nexthop; + struct flowi4 *fl4; + struct rtable *rt; + int err; + struct ip_options_rcu *inet_opt; + + if (addr_len < sizeof(struct sockaddr_in)) + return -EINVAL; + + if (usin->sin_family != AF_INET) + return -EAFNOSUPPORT; + + nexthop = daddr = usin->sin_addr.s_addr; + inet_opt = rcu_dereference_protected(inet->inet_opt, + sock_owned_by_user(sk)); + if (inet_opt && inet_opt->opt.srr) { + if (!daddr) + return -EINVAL; + nexthop = inet_opt->opt.faddr; + } + + orig_sport = inet->inet_sport; + orig_dport = usin->sin_port; + fl4 = &inet->cork.fl.u.ip4; + rt = ip_route_connect(fl4, nexthop, inet->inet_saddr, + RT_CONN_FLAGS(sk), sk->sk_bound_dev_if, + IPPROTO_TCP, + orig_sport, orig_dport, sk, true); + if (IS_ERR(rt)) { + err = PTR_ERR(rt); + if (err == -ENETUNREACH) + IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); + return err; + } + + if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { + ip_rt_put(rt); + return -ENETUNREACH; + } + + if (!inet_opt || !inet_opt->opt.srr) + daddr = fl4->daddr; + + if (!inet->inet_saddr) + inet->inet_saddr = fl4->saddr; + inet->inet_rcv_saddr = inet->inet_saddr; + + if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) { + /* Reset inherited state */ + tp->rx_opt.ts_recent = 0; + tp->rx_opt.ts_recent_stamp = 0; + tp->write_seq = 0; + } + + if (tcp_death_row.sysctl_tw_recycle && + !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) { + struct inet_peer *peer = rt_get_peer(rt, fl4->daddr); + /* + * VJ's idea. We save last timestamp seen from + * the destination in peer table, when entering state + * TIME-WAIT * and initialize rx_opt.ts_recent from it, + * when trying new connection. + */ + if (peer) { + inet_peer_refcheck(peer); + if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) { + tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp; + tp->rx_opt.ts_recent = peer->tcp_ts; + } + } + } + + inet->inet_dport = usin->sin_port; + inet->inet_daddr = daddr; + + inet_csk(sk)->icsk_ext_hdr_len = 0; + if (inet_opt) + inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen; + + tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT; + + /* Socket identity is still unknown (sport may be zero). + * However we set state to SYN-SENT and not releasing socket + * lock select source port, enter ourselves into the hash tables and + * complete initialization after this. + */ + tcp_set_state(sk, TCP_SYN_SENT); + err = inet_hash_connect(&tcp_death_row, sk); + if (err) + goto failure; + + rt = ip_route_newports(fl4, rt, orig_sport, orig_dport, + inet->inet_sport, inet->inet_dport, sk); + if (IS_ERR(rt)) { + err = PTR_ERR(rt); + rt = NULL; + goto failure; + } + /* OK, now commit destination to socket. */ + sk->sk_gso_type = SKB_GSO_TCPV4; + sk_setup_caps(sk, &rt->dst); + + if (!tp->write_seq) + tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr, + inet->inet_daddr, + inet->inet_sport, + usin->sin_port); + + inet->inet_id = tp->write_seq ^ jiffies; + + err = tcp_connect(sk); + rt = NULL; + if (err) + goto failure; + + return 0; + +failure: + /* + * This unhashes the socket and releases the local port, + * if necessary. + */ + tcp_set_state(sk, TCP_CLOSE); + ip_rt_put(rt); + sk->sk_route_caps = 0; + inet->inet_dport = 0; + return err; +} +EXPORT_SYMBOL(tcp_v4_connect); + +/* + * This routine does path mtu discovery as defined in RFC1191. + */ +static void do_pmtu_discovery(struct sock *sk, const struct iphdr *iph, u32 mtu) +{ + struct dst_entry *dst; + struct inet_sock *inet = inet_sk(sk); + + /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs + * send out by Linux are always <576bytes so they should go through + * unfragmented). + */ + if (sk->sk_state == TCP_LISTEN) + return; + + /* We don't check in the destentry if pmtu discovery is forbidden + * on this route. We just assume that no packet_to_big packets + * are send back when pmtu discovery is not active. + * There is a small race when the user changes this flag in the + * route, but I think that's acceptable. + */ + if ((dst = __sk_dst_check(sk, 0)) == NULL) + return; + + dst->ops->update_pmtu(dst, mtu); + + /* Something is about to be wrong... Remember soft error + * for the case, if this connection will not able to recover. + */ + if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) + sk->sk_err_soft = EMSGSIZE; + + mtu = dst_mtu(dst); + + if (inet->pmtudisc != IP_PMTUDISC_DONT && + inet_csk(sk)->icsk_pmtu_cookie > mtu) { + tcp_sync_mss(sk, mtu); + + /* Resend the TCP packet because it's + * clear that the old packet has been + * dropped. This is the new "fast" path mtu + * discovery. + */ + tcp_simple_retransmit(sk); + } /* else let the usual retransmit timer handle it */ +} + +/* + * This routine is called by the ICMP module when it gets some + * sort of error condition. If err < 0 then the socket should + * be closed and the error returned to the user. If err > 0 + * it's just the icmp type << 8 | icmp code. After adjustment + * header points to the first 8 bytes of the tcp header. We need + * to find the appropriate port. + * + * The locking strategy used here is very "optimistic". When + * someone else accesses the socket the ICMP is just dropped + * and for some paths there is no check at all. + * A more general error queue to queue errors for later handling + * is probably better. + * + */ + +void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) +{ + const struct iphdr *iph = (const struct iphdr *)icmp_skb->data; + struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2)); + struct inet_connection_sock *icsk; + struct tcp_sock *tp; + struct inet_sock *inet; + const int type = icmp_hdr(icmp_skb)->type; + const int code = icmp_hdr(icmp_skb)->code; + struct sock *sk; + struct sk_buff *skb; + __u32 seq; + __u32 remaining; + int err; + struct net *net = dev_net(icmp_skb->dev); + + if (icmp_skb->len < (iph->ihl << 2) + 8) { + ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); + return; + } + + sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest, + iph->saddr, th->source, inet_iif(icmp_skb)); + if (!sk) { + ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); + return; + } + if (sk->sk_state == TCP_TIME_WAIT) { + inet_twsk_put(inet_twsk(sk)); + return; + } + + bh_lock_sock(sk); + /* If too many ICMPs get dropped on busy + * servers this needs to be solved differently. + */ + if (sock_owned_by_user(sk)) + NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); + + if (sk->sk_state == TCP_CLOSE) + goto out; + + if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) { + NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP); + goto out; + } + + icsk = inet_csk(sk); + tp = tcp_sk(sk); + seq = ntohl(th->seq); + if (sk->sk_state != TCP_LISTEN && + !between(seq, tp->snd_una, tp->snd_nxt)) { + NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS); + goto out; + } + + switch (type) { + case ICMP_SOURCE_QUENCH: + /* Just silently ignore these. */ + goto out; + case ICMP_PARAMETERPROB: + err = EPROTO; + break; + case ICMP_DEST_UNREACH: + if (code > NR_ICMP_UNREACH) + goto out; + + if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ + if (!sock_owned_by_user(sk)) + do_pmtu_discovery(sk, iph, info); + goto out; + } + + err = icmp_err_convert[code].errno; + /* check if icmp_skb allows revert of backoff + * (see draft-zimmermann-tcp-lcd) */ + if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH) + break; + if (seq != tp->snd_una || !icsk->icsk_retransmits || + !icsk->icsk_backoff) + break; + + if (sock_owned_by_user(sk)) + break; + + icsk->icsk_backoff--; + inet_csk(sk)->icsk_rto = (tp->srtt ? __tcp_set_rto(tp) : + TCP_TIMEOUT_INIT) << icsk->icsk_backoff; + tcp_bound_rto(sk); + + skb = tcp_write_queue_head(sk); + BUG_ON(!skb); + + remaining = icsk->icsk_rto - min(icsk->icsk_rto, + tcp_time_stamp - TCP_SKB_CB(skb)->when); + + if (remaining) { + inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, + remaining, TCP_RTO_MAX); + } else { + /* RTO revert clocked out retransmission. + * Will retransmit now */ + tcp_retransmit_timer(sk); + } + + break; + case ICMP_TIME_EXCEEDED: + err = EHOSTUNREACH; + break; + default: + goto out; + } + + switch (sk->sk_state) { + struct request_sock *req, **prev; + case TCP_LISTEN: + if (sock_owned_by_user(sk)) + goto out; + + req = inet_csk_search_req(sk, &prev, th->dest, + iph->daddr, iph->saddr); + if (!req) + goto out; + + /* ICMPs are not backlogged, hence we cannot get + an established socket here. + */ + WARN_ON(req->sk); + + if (seq != tcp_rsk(req)->snt_isn) { + NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS); + goto out; + } + + /* + * Still in SYN_RECV, just remove it silently. + * There is no good way to pass the error to the newly + * created socket, and POSIX does not want network + * errors returned from accept(). + */ + inet_csk_reqsk_queue_drop(sk, req, prev); + goto out; + + case TCP_SYN_SENT: + case TCP_SYN_RECV: /* Cannot happen. + It can f.e. if SYNs crossed. + */ + if (!sock_owned_by_user(sk)) { + sk->sk_err = err; + + sk->sk_error_report(sk); + + tcp_done(sk); + } else { + sk->sk_err_soft = err; + } + goto out; + } + + /* If we've already connected we will keep trying + * until we time out, or the user gives up. + * + * rfc1122 4.2.3.9 allows to consider as hard errors + * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, + * but it is obsoleted by pmtu discovery). + * + * Note, that in modern internet, where routing is unreliable + * and in each dark corner broken firewalls sit, sending random + * errors ordered by their masters even this two messages finally lose + * their original sense (even Linux sends invalid PORT_UNREACHs) + * + * Now we are in compliance with RFCs. + * --ANK (980905) + */ + + inet = inet_sk(sk); + if (!sock_owned_by_user(sk) && inet->recverr) { + sk->sk_err = err; + sk->sk_error_report(sk); + } else { /* Only an error on timeout */ + sk->sk_err_soft = err; + } + +out: + bh_unlock_sock(sk); + sock_put(sk); +} + +static void __tcp_v4_send_check(struct sk_buff *skb, + __be32 saddr, __be32 daddr) +{ + struct tcphdr *th = tcp_hdr(skb); + + if (skb->ip_summed == CHECKSUM_PARTIAL) { + th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0); + skb->csum_start = skb_transport_header(skb) - skb->head; + skb->csum_offset = offsetof(struct tcphdr, check); + } else { + th->check = tcp_v4_check(skb->len, saddr, daddr, + csum_partial(th, + th->doff << 2, + skb->csum)); + } +} + +/* This routine computes an IPv4 TCP checksum. */ +void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) +{ + const struct inet_sock *inet = inet_sk(sk); + + __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr); +} +EXPORT_SYMBOL(tcp_v4_send_check); + +int tcp_v4_gso_send_check(struct sk_buff *skb) +{ + const struct iphdr *iph; + struct tcphdr *th; + + if (!pskb_may_pull(skb, sizeof(*th))) + return -EINVAL; + + iph = ip_hdr(skb); + th = tcp_hdr(skb); + + th->check = 0; + skb->ip_summed = CHECKSUM_PARTIAL; + __tcp_v4_send_check(skb, iph->saddr, iph->daddr); + return 0; +} + +/* + * This routine will send an RST to the other tcp. + * + * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.) + * for reset. + * Answer: if a packet caused RST, it is not for a socket + * existing in our system, if it is matched to a socket, + * it is just duplicate segment or bug in other side's TCP. + * So that we build reply only basing on parameters + * arrived with segment. + * Exception: precedence violation. We do not implement it in any case. + */ + +static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb) +{ + const struct tcphdr *th = tcp_hdr(skb); + struct { + struct tcphdr th; +#ifdef CONFIG_TCP_MD5SIG + __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)]; +#endif + } rep; + struct ip_reply_arg arg; +#ifdef CONFIG_TCP_MD5SIG + struct tcp_md5sig_key *key; + const __u8 *hash_location = NULL; + unsigned char newhash[16]; + int genhash; + struct sock *sk1 = NULL; +#endif + struct net *net; + + /* Never send a reset in response to a reset. */ + if (th->rst) + return; + + if (skb_rtable(skb)->rt_type != RTN_LOCAL) + return; + + /* Swap the send and the receive. */ + memset(&rep, 0, sizeof(rep)); + rep.th.dest = th->source; + rep.th.source = th->dest; + rep.th.doff = sizeof(struct tcphdr) / 4; + rep.th.rst = 1; + + if (th->ack) { + rep.th.seq = th->ack_seq; + } else { + rep.th.ack = 1; + rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin + + skb->len - (th->doff << 2)); + } + + memset(&arg, 0, sizeof(arg)); + arg.iov[0].iov_base = (unsigned char *)&rep; + arg.iov[0].iov_len = sizeof(rep.th); + +#ifdef CONFIG_TCP_MD5SIG + hash_location = tcp_parse_md5sig_option(th); + if (!sk && hash_location) { + /* + * active side is lost. Try to find listening socket through + * source port, and then find md5 key through listening socket. + * we are not loose security here: + * Incoming packet is checked with md5 hash with finding key, + * no RST generated if md5 hash doesn't match. + */ + sk1 = __inet_lookup_listener(dev_net(skb_dst(skb)->dev), + &tcp_hashinfo, ip_hdr(skb)->daddr, + ntohs(th->source), inet_iif(skb)); + /* don't send rst if it can't find key */ + if (!sk1) + return; + rcu_read_lock(); + key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *) + &ip_hdr(skb)->saddr, AF_INET); + if (!key) + goto release_sk1; + + genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, NULL, skb); + if (genhash || memcmp(hash_location, newhash, 16) != 0) + goto release_sk1; + } else { + key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *) + &ip_hdr(skb)->saddr, + AF_INET) : NULL; + } + + if (key) { + rep.opt[0] = htonl((TCPOPT_NOP << 24) | + (TCPOPT_NOP << 16) | + (TCPOPT_MD5SIG << 8) | + TCPOLEN_MD5SIG); + /* Update length and the length the header thinks exists */ + arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; + rep.th.doff = arg.iov[0].iov_len / 4; + + tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1], + key, ip_hdr(skb)->saddr, + ip_hdr(skb)->daddr, &rep.th); + } +#endif + arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, + ip_hdr(skb)->saddr, /* XXX */ + arg.iov[0].iov_len, IPPROTO_TCP, 0); + arg.csumoffset = offsetof(struct tcphdr, check) / 2; + arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0; + /* When socket is gone, all binding information is lost. + * routing might fail in this case. using iif for oif to + * make sure we can deliver it + */ + arg.bound_dev_if = sk ? sk->sk_bound_dev_if : inet_iif(skb); + + net = dev_net(skb_dst(skb)->dev); + arg.tos = ip_hdr(skb)->tos; + ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr, + &arg, arg.iov[0].iov_len); + + TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS); + TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS); + +#ifdef CONFIG_TCP_MD5SIG +release_sk1: + if (sk1) { + rcu_read_unlock(); + sock_put(sk1); + } +#endif +} + +/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states + outside socket context is ugly, certainly. What can I do? + */ + +static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, + u32 win, u32 ts, int oif, + struct tcp_md5sig_key *key, + int reply_flags, u8 tos) +{ + const struct tcphdr *th = tcp_hdr(skb); + struct { + struct tcphdr th; + __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2) +#ifdef CONFIG_TCP_MD5SIG + + (TCPOLEN_MD5SIG_ALIGNED >> 2) +#endif + ]; + } rep; + struct ip_reply_arg arg; + struct net *net = dev_net(skb_dst(skb)->dev); + + memset(&rep.th, 0, sizeof(struct tcphdr)); + memset(&arg, 0, sizeof(arg)); + + arg.iov[0].iov_base = (unsigned char *)&rep; + arg.iov[0].iov_len = sizeof(rep.th); + if (ts) { + rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | + (TCPOPT_TIMESTAMP << 8) | + TCPOLEN_TIMESTAMP); + rep.opt[1] = htonl(tcp_time_stamp); + rep.opt[2] = htonl(ts); + arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED; + } + + /* Swap the send and the receive. */ + rep.th.dest = th->source; + rep.th.source = th->dest; + rep.th.doff = arg.iov[0].iov_len / 4; + rep.th.seq = htonl(seq); + rep.th.ack_seq = htonl(ack); + rep.th.ack = 1; + rep.th.window = htons(win); + +#ifdef CONFIG_TCP_MD5SIG + if (key) { + int offset = (ts) ? 3 : 0; + + rep.opt[offset++] = htonl((TCPOPT_NOP << 24) | + (TCPOPT_NOP << 16) | + (TCPOPT_MD5SIG << 8) | + TCPOLEN_MD5SIG); + arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; + rep.th.doff = arg.iov[0].iov_len/4; + + tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset], + key, ip_hdr(skb)->saddr, + ip_hdr(skb)->daddr, &rep.th); + } +#endif + arg.flags = reply_flags; + arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, + ip_hdr(skb)->saddr, /* XXX */ + arg.iov[0].iov_len, IPPROTO_TCP, 0); + arg.csumoffset = offsetof(struct tcphdr, check) / 2; + if (oif) + arg.bound_dev_if = oif; + arg.tos = tos; + ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr, + &arg, arg.iov[0].iov_len); + + TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS); +} + +static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) +{ + struct inet_timewait_sock *tw = inet_twsk(sk); + struct tcp_timewait_sock *tcptw = tcp_twsk(sk); + + tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, + tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, + tcptw->tw_ts_recent, + tw->tw_bound_dev_if, + tcp_twsk_md5_key(tcptw), + tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0, + tw->tw_tos + ); + + inet_twsk_put(tw); +} + +static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, + struct request_sock *req) +{ + tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1, + tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, + req->ts_recent, + 0, + tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr, + AF_INET), + inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, + ip_hdr(skb)->tos); +} + +/* + * Send a SYN-ACK after having received a SYN. + * This still operates on a request_sock only, not on a big + * socket. + */ +static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst, + struct request_sock *req, + struct request_values *rvp) +{ + const struct inet_request_sock *ireq = inet_rsk(req); + struct flowi4 fl4; + int err = -1; + struct sk_buff * skb; + + /* First, grab a route. */ + if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL) + return -1; + + skb = tcp_make_synack(sk, dst, req, rvp); + + if (skb) { + __tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr); + + err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr, + ireq->rmt_addr, + ireq->opt); + err = net_xmit_eval(err); + } + + dst_release(dst); + return err; +} + +static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req, + struct request_values *rvp) +{ + TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS); + return tcp_v4_send_synack(sk, NULL, req, rvp); +} + +/* + * IPv4 request_sock destructor. + */ +static void tcp_v4_reqsk_destructor(struct request_sock *req) +{ + kfree(inet_rsk(req)->opt); +} + +/* + * Return 1 if a syncookie should be sent + */ +int tcp_syn_flood_action(struct sock *sk, + const struct sk_buff *skb, + const char *proto) +{ + const char *msg = "Dropping request"; + int want_cookie = 0; + struct listen_sock *lopt; + + + +#ifdef CONFIG_SYN_COOKIES + if (sysctl_tcp_syncookies) { + msg = "Sending cookies"; + want_cookie = 1; + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES); + } else +#endif + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP); + + lopt = inet_csk(sk)->icsk_accept_queue.listen_opt; + if (!lopt->synflood_warned) { + lopt->synflood_warned = 1; + pr_info("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n", + proto, ntohs(tcp_hdr(skb)->dest), msg); + } + return want_cookie; +} +EXPORT_SYMBOL(tcp_syn_flood_action); + +/* + * Save and compile IPv4 options into the request_sock if needed. + */ +static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk, + struct sk_buff *skb) +{ + const struct ip_options *opt = &(IPCB(skb)->opt); + struct ip_options_rcu *dopt = NULL; + + if (opt && opt->optlen) { + int opt_size = sizeof(*dopt) + opt->optlen; + + dopt = kmalloc(opt_size, GFP_ATOMIC); + if (dopt) { + if (ip_options_echo(&dopt->opt, skb)) { + kfree(dopt); + dopt = NULL; + } + } + } + return dopt; +} + +#ifdef CONFIG_TCP_MD5SIG +/* + * RFC2385 MD5 checksumming requires a mapping of + * IP address->MD5 Key. + * We need to maintain these in the sk structure. + */ + +/* Find the Key structure for an address. */ +struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk, + const union tcp_md5_addr *addr, + int family) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_md5sig_key *key; + struct hlist_node *pos; + unsigned int size = sizeof(struct in_addr); + struct tcp_md5sig_info *md5sig; + + /* caller either holds rcu_read_lock() or socket lock */ + md5sig = rcu_dereference_check(tp->md5sig_info, + sock_owned_by_user(sk) || + lockdep_is_held(&sk->sk_lock.slock)); + if (!md5sig) + return NULL; +#if IS_ENABLED(CONFIG_IPV6) + if (family == AF_INET6) + size = sizeof(struct in6_addr); +#endif + hlist_for_each_entry_rcu(key, pos, &md5sig->head, node) { + if (key->family != family) + continue; + if (!memcmp(&key->addr, addr, size)) + return key; + } + return NULL; +} +EXPORT_SYMBOL(tcp_md5_do_lookup); + +struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk, + struct sock *addr_sk) +{ + union tcp_md5_addr *addr; + + addr = (union tcp_md5_addr *)&inet_sk(addr_sk)->inet_daddr; + return tcp_md5_do_lookup(sk, addr, AF_INET); +} +EXPORT_SYMBOL(tcp_v4_md5_lookup); + +static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk, + struct request_sock *req) +{ + union tcp_md5_addr *addr; + + addr = (union tcp_md5_addr *)&inet_rsk(req)->rmt_addr; + return tcp_md5_do_lookup(sk, addr, AF_INET); +} + +/* This can be called on a newly created socket, from other files */ +int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, + int family, const u8 *newkey, u8 newkeylen, gfp_t gfp) +{ + /* Add Key to the list */ + struct tcp_md5sig_key *key; + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_md5sig_info *md5sig; + + key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&addr, AF_INET); + if (key) { + /* Pre-existing entry - just update that one. */ + memcpy(key->key, newkey, newkeylen); + key->keylen = newkeylen; + return 0; + } + + md5sig = rcu_dereference_protected(tp->md5sig_info, + sock_owned_by_user(sk)); + if (!md5sig) { + md5sig = kmalloc(sizeof(*md5sig), gfp); + if (!md5sig) + return -ENOMEM; + + sk_nocaps_add(sk, NETIF_F_GSO_MASK); + INIT_HLIST_HEAD(&md5sig->head); + rcu_assign_pointer(tp->md5sig_info, md5sig); + } + + key = sock_kmalloc(sk, sizeof(*key), gfp); + if (!key) + return -ENOMEM; + if (hlist_empty(&md5sig->head) && !tcp_alloc_md5sig_pool(sk)) { + sock_kfree_s(sk, key, sizeof(*key)); + return -ENOMEM; + } + + memcpy(key->key, newkey, newkeylen); + key->keylen = newkeylen; + key->family = family; + memcpy(&key->addr, addr, + (family == AF_INET6) ? sizeof(struct in6_addr) : + sizeof(struct in_addr)); + hlist_add_head_rcu(&key->node, &md5sig->head); + return 0; +} +EXPORT_SYMBOL(tcp_md5_do_add); + +int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_md5sig_key *key; + struct tcp_md5sig_info *md5sig; + + key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&addr, AF_INET); + if (!key) + return -ENOENT; + hlist_del_rcu(&key->node); + atomic_sub(sizeof(*key), &sk->sk_omem_alloc); + kfree_rcu(key, rcu); + md5sig = rcu_dereference_protected(tp->md5sig_info, + sock_owned_by_user(sk)); + if (hlist_empty(&md5sig->head)) + tcp_free_md5sig_pool(); + return 0; +} +EXPORT_SYMBOL(tcp_md5_do_del); + +void tcp_clear_md5_list(struct sock *sk) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_md5sig_key *key; + struct hlist_node *pos, *n; + struct tcp_md5sig_info *md5sig; + + md5sig = rcu_dereference_protected(tp->md5sig_info, 1); + + if (!hlist_empty(&md5sig->head)) + tcp_free_md5sig_pool(); + hlist_for_each_entry_safe(key, pos, n, &md5sig->head, node) { + hlist_del_rcu(&key->node); + atomic_sub(sizeof(*key), &sk->sk_omem_alloc); + kfree_rcu(key, rcu); + } +} + +static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval, + int optlen) +{ + struct tcp_md5sig cmd; + struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr; + + if (optlen < sizeof(cmd)) + return -EINVAL; + + if (copy_from_user(&cmd, optval, sizeof(cmd))) + return -EFAULT; + + if (sin->sin_family != AF_INET) + return -EINVAL; + + if (!cmd.tcpm_key || !cmd.tcpm_keylen) + return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, + AF_INET); + + if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) + return -EINVAL; + + return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, + AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, + GFP_KERNEL); +} + +static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp, + __be32 daddr, __be32 saddr, int nbytes) +{ + struct tcp4_pseudohdr *bp; + struct scatterlist sg; + + bp = &hp->md5_blk.ip4; + + /* + * 1. the TCP pseudo-header (in the order: source IP address, + * destination IP address, zero-padded protocol number, and + * segment length) + */ + bp->saddr = saddr; + bp->daddr = daddr; + bp->pad = 0; + bp->protocol = IPPROTO_TCP; + bp->len = cpu_to_be16(nbytes); + + sg_init_one(&sg, bp, sizeof(*bp)); + return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp)); +} + +static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, + __be32 daddr, __be32 saddr, const struct tcphdr *th) +{ + struct tcp_md5sig_pool *hp; + struct hash_desc *desc; + + hp = tcp_get_md5sig_pool(); + if (!hp) + goto clear_hash_noput; + desc = &hp->md5_desc; + + if (crypto_hash_init(desc)) + goto clear_hash; + if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2)) + goto clear_hash; + if (tcp_md5_hash_header(hp, th)) + goto clear_hash; + if (tcp_md5_hash_key(hp, key)) + goto clear_hash; + if (crypto_hash_final(desc, md5_hash)) + goto clear_hash; + + tcp_put_md5sig_pool(); + return 0; + +clear_hash: + tcp_put_md5sig_pool(); +clear_hash_noput: + memset(md5_hash, 0, 16); + return 1; +} + +int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key, + const struct sock *sk, const struct request_sock *req, + const struct sk_buff *skb) +{ + struct tcp_md5sig_pool *hp; + struct hash_desc *desc; + const struct tcphdr *th = tcp_hdr(skb); + __be32 saddr, daddr; + + if (sk) { + saddr = inet_sk(sk)->inet_saddr; + daddr = inet_sk(sk)->inet_daddr; + } else if (req) { + saddr = inet_rsk(req)->loc_addr; + daddr = inet_rsk(req)->rmt_addr; + } else { + const struct iphdr *iph = ip_hdr(skb); + saddr = iph->saddr; + daddr = iph->daddr; + } + + hp = tcp_get_md5sig_pool(); + if (!hp) + goto clear_hash_noput; + desc = &hp->md5_desc; + + if (crypto_hash_init(desc)) + goto clear_hash; + + if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len)) + goto clear_hash; + if (tcp_md5_hash_header(hp, th)) + goto clear_hash; + if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) + goto clear_hash; + if (tcp_md5_hash_key(hp, key)) + goto clear_hash; + if (crypto_hash_final(desc, md5_hash)) + goto clear_hash; + + tcp_put_md5sig_pool(); + return 0; + +clear_hash: + tcp_put_md5sig_pool(); +clear_hash_noput: + memset(md5_hash, 0, 16); + return 1; +} +EXPORT_SYMBOL(tcp_v4_md5_hash_skb); + +static int tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb) +{ + /* + * This gets called for each TCP segment that arrives + * so we want to be efficient. + * We have 3 drop cases: + * o No MD5 hash and one expected. + * o MD5 hash and we're not expecting one. + * o MD5 hash and its wrong. + */ + const __u8 *hash_location = NULL; + struct tcp_md5sig_key *hash_expected; + const struct iphdr *iph = ip_hdr(skb); + const struct tcphdr *th = tcp_hdr(skb); + int genhash; + unsigned char newhash[16]; + + hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr, + AF_INET); + hash_location = tcp_parse_md5sig_option(th); + + /* We've parsed the options - do we have a hash? */ + if (!hash_expected && !hash_location) + return 0; + + if (hash_expected && !hash_location) { + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); + return 1; + } + + if (!hash_expected && hash_location) { + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED); + return 1; + } + + /* Okay, so this is hash_expected and hash_location - + * so we need to calculate the checksum. + */ + genhash = tcp_v4_md5_hash_skb(newhash, + hash_expected, + NULL, NULL, skb); + + if (genhash || memcmp(hash_location, newhash, 16) != 0) { + if (net_ratelimit()) { + pr_info("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n", + &iph->saddr, ntohs(th->source), + &iph->daddr, ntohs(th->dest), + genhash ? " tcp_v4_calc_md5_hash failed" : ""); + } + return 1; + } + return 0; +} + +#endif + +struct request_sock_ops tcp_request_sock_ops __read_mostly = { + .family = PF_INET, + .obj_size = sizeof(struct tcp_request_sock), + .rtx_syn_ack = tcp_v4_rtx_synack, + .send_ack = tcp_v4_reqsk_send_ack, + .destructor = tcp_v4_reqsk_destructor, + .send_reset = tcp_v4_send_reset, + .syn_ack_timeout = tcp_syn_ack_timeout, +}; + +#ifdef CONFIG_TCP_MD5SIG +static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { + .md5_lookup = tcp_v4_reqsk_md5_lookup, + .calc_md5_hash = tcp_v4_md5_hash_skb, +}; +#endif + +int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) +{ + struct tcp_extend_values tmp_ext; + struct tcp_options_received tmp_opt; + const u8 *hash_location; + struct request_sock *req; + struct inet_request_sock *ireq; + struct tcp_sock *tp = tcp_sk(sk); + struct dst_entry *dst = NULL; + __be32 saddr = ip_hdr(skb)->saddr; + __be32 daddr = ip_hdr(skb)->daddr; + __u32 isn = TCP_SKB_CB(skb)->when; + int want_cookie = 0; + + /* Never answer to SYNs send to broadcast or multicast */ + if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) + goto drop; + + /* TW buckets are converted to open requests without + * limitations, they conserve resources and peer is + * evidently real one. + */ + if (inet_csk_reqsk_queue_is_full(sk) && !isn) { + want_cookie = tcp_syn_flood_action(sk, skb, "TCP"); + if (!want_cookie) + goto drop; + } + + /* Accept backlog is full. If we have already queued enough + * of warm entries in syn queue, drop request. It is better than + * clogging syn queue with openreqs with exponentially increasing + * timeout. + */ + if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) + goto drop; + + req = inet_reqsk_alloc(&tcp_request_sock_ops); + if (!req) + goto drop; + +#ifdef CONFIG_TCP_MD5SIG + tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops; +#endif + + tcp_clear_options(&tmp_opt); + tmp_opt.mss_clamp = TCP_MSS_DEFAULT; + tmp_opt.user_mss = tp->rx_opt.user_mss; + tcp_parse_options(skb, &tmp_opt, &hash_location, 0); + + if (tmp_opt.cookie_plus > 0 && + tmp_opt.saw_tstamp && + !tp->rx_opt.cookie_out_never && + (sysctl_tcp_cookie_size > 0 || + (tp->cookie_values != NULL && + tp->cookie_values->cookie_desired > 0))) { + u8 *c; + u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS]; + int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE; + + if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0) + goto drop_and_release; + + /* Secret recipe starts with IP addresses */ + *mess++ ^= (__force u32)daddr; + *mess++ ^= (__force u32)saddr; + + /* plus variable length Initiator Cookie */ + c = (u8 *)mess; + while (l-- > 0) + *c++ ^= *hash_location++; + + want_cookie = 0; /* not our kind of cookie */ + tmp_ext.cookie_out_never = 0; /* false */ + tmp_ext.cookie_plus = tmp_opt.cookie_plus; + } else if (!tp->rx_opt.cookie_in_always) { + /* redundant indications, but ensure initialization. */ + tmp_ext.cookie_out_never = 1; /* true */ + tmp_ext.cookie_plus = 0; + } else { + goto drop_and_release; + } + tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always; + + if (want_cookie && !tmp_opt.saw_tstamp) + tcp_clear_options(&tmp_opt); + + tmp_opt.tstamp_ok = tmp_opt.saw_tstamp; + tcp_openreq_init(req, &tmp_opt, skb); + + ireq = inet_rsk(req); + ireq->loc_addr = daddr; + ireq->rmt_addr = saddr; + ireq->no_srccheck = inet_sk(sk)->transparent; + ireq->opt = tcp_v4_save_options(sk, skb); + + if (security_inet_conn_request(sk, skb, req)) + goto drop_and_free; + + if (!want_cookie || tmp_opt.tstamp_ok) + TCP_ECN_create_request(req, tcp_hdr(skb)); + + if (want_cookie) { + isn = cookie_v4_init_sequence(sk, skb, &req->mss); + req->cookie_ts = tmp_opt.tstamp_ok; + } else if (!isn) { + struct inet_peer *peer = NULL; + struct flowi4 fl4; + + /* VJ's idea. We save last timestamp seen + * from the destination in peer table, when entering + * state TIME-WAIT, and check against it before + * accepting new connection request. + * + * If "isn" is not zero, this request hit alive + * timewait bucket, so that all the necessary checks + * are made in the function processing timewait state. + */ + if (tmp_opt.saw_tstamp && + tcp_death_row.sysctl_tw_recycle && + (dst = inet_csk_route_req(sk, &fl4, req)) != NULL && + fl4.daddr == saddr && + (peer = rt_get_peer((struct rtable *)dst, fl4.daddr)) != NULL) { + inet_peer_refcheck(peer); + if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL && + (s32)(peer->tcp_ts - req->ts_recent) > + TCP_PAWS_WINDOW) { + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED); + goto drop_and_release; + } + } + /* Kill the following clause, if you dislike this way. */ + else if (!sysctl_tcp_syncookies && + (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) < + (sysctl_max_syn_backlog >> 2)) && + (!peer || !peer->tcp_ts_stamp) && + (!dst || !dst_metric(dst, RTAX_RTT))) { + /* Without syncookies last quarter of + * backlog is filled with destinations, + * proven to be alive. + * It means that we continue to communicate + * to destinations, already remembered + * to the moment of synflood. + */ + LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("drop open request from %pI4/%u\n"), + &saddr, ntohs(tcp_hdr(skb)->source)); + goto drop_and_release; + } + + isn = tcp_v4_init_sequence(skb); + } + tcp_rsk(req)->snt_isn = isn; + tcp_rsk(req)->snt_synack = tcp_time_stamp; + + if (tcp_v4_send_synack(sk, dst, req, + (struct request_values *)&tmp_ext) || + want_cookie) + goto drop_and_free; + + inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT); + return 0; + +drop_and_release: + dst_release(dst); +drop_and_free: + reqsk_free(req); +drop: + return 0; +} +EXPORT_SYMBOL(tcp_v4_conn_request); + + +/* + * The three way handshake has completed - we got a valid synack - + * now create the new socket. + */ +struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, + struct request_sock *req, + struct dst_entry *dst) +{ + struct inet_request_sock *ireq; + struct inet_sock *newinet; + struct tcp_sock *newtp; + struct sock *newsk; +#ifdef CONFIG_TCP_MD5SIG + struct tcp_md5sig_key *key; +#endif + struct ip_options_rcu *inet_opt; + + if (sk_acceptq_is_full(sk)) + goto exit_overflow; + + newsk = tcp_create_openreq_child(sk, req, skb); + if (!newsk) + goto exit_nonewsk; + + newsk->sk_gso_type = SKB_GSO_TCPV4; + + newtp = tcp_sk(newsk); + newinet = inet_sk(newsk); + ireq = inet_rsk(req); + newinet->inet_daddr = ireq->rmt_addr; + newinet->inet_rcv_saddr = ireq->loc_addr; + newinet->inet_saddr = ireq->loc_addr; + inet_opt = ireq->opt; + rcu_assign_pointer(newinet->inet_opt, inet_opt); + ireq->opt = NULL; + newinet->mc_index = inet_iif(skb); + newinet->mc_ttl = ip_hdr(skb)->ttl; + newinet->rcv_tos = ip_hdr(skb)->tos; + inet_csk(newsk)->icsk_ext_hdr_len = 0; + if (inet_opt) + inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; + newinet->inet_id = newtp->write_seq ^ jiffies; + + if (!dst) { + dst = inet_csk_route_child_sock(sk, newsk, req); + if (!dst) + goto put_and_exit; + } else { + /* syncookie case : see end of cookie_v4_check() */ + } + sk_setup_caps(newsk, dst); + + tcp_mtup_init(newsk); + tcp_sync_mss(newsk, dst_mtu(dst)); + newtp->advmss = dst_metric_advmss(dst); + if (tcp_sk(sk)->rx_opt.user_mss && + tcp_sk(sk)->rx_opt.user_mss < newtp->advmss) + newtp->advmss = tcp_sk(sk)->rx_opt.user_mss; + + tcp_initialize_rcv_mss(newsk); + if (tcp_rsk(req)->snt_synack) + tcp_valid_rtt_meas(newsk, + tcp_time_stamp - tcp_rsk(req)->snt_synack); + newtp->total_retrans = req->retrans; + +#ifdef CONFIG_TCP_MD5SIG + /* Copy over the MD5 key from the original socket */ + key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr, + AF_INET); + if (key != NULL) { + /* + * We're using one, so create a matching key + * on the newsk structure. If we fail to get + * memory, then we end up not copying the key + * across. Shucks. + */ + tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr, + AF_INET, key->key, key->keylen, GFP_ATOMIC); + sk_nocaps_add(newsk, NETIF_F_GSO_MASK); + } +#endif + + if (__inet_inherit_port(sk, newsk) < 0) + goto put_and_exit; + __inet_hash_nolisten(newsk, NULL); + + return newsk; + +exit_overflow: + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); +exit_nonewsk: + dst_release(dst); +exit: + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); + return NULL; +put_and_exit: + tcp_clear_xmit_timers(newsk); + tcp_cleanup_congestion_control(newsk); + bh_unlock_sock(newsk); + sock_put(newsk); + goto exit; +} +EXPORT_SYMBOL(tcp_v4_syn_recv_sock); + +static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb) +{ + struct tcphdr *th = tcp_hdr(skb); + const struct iphdr *iph = ip_hdr(skb); + struct sock *nsk; + struct request_sock **prev; + /* Find possible connection requests. */ + struct request_sock *req = inet_csk_search_req(sk, &prev, th->source, + iph->saddr, iph->daddr); + if (req) + return tcp_check_req(sk, skb, req, prev); + + nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr, + th->source, iph->daddr, th->dest, inet_iif(skb)); + + if (nsk) { + if (nsk->sk_state != TCP_TIME_WAIT) { + bh_lock_sock(nsk); + return nsk; + } + inet_twsk_put(inet_twsk(nsk)); + return NULL; + } + +#ifdef CONFIG_SYN_COOKIES + if (!th->syn) + sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt)); +#endif + return sk; +} + +static __sum16 tcp_v4_checksum_init(struct sk_buff *skb) +{ + const struct iphdr *iph = ip_hdr(skb); + + if (skb->ip_summed == CHECKSUM_COMPLETE) { + if (!tcp_v4_check(skb->len, iph->saddr, + iph->daddr, skb->csum)) { + skb->ip_summed = CHECKSUM_UNNECESSARY; + return 0; + } + } + + skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, + skb->len, IPPROTO_TCP, 0); + + if (skb->len <= 76) { + return __skb_checksum_complete(skb); + } + return 0; +} + + +/* The socket must have it's spinlock held when we get + * here. + * + * We have a potential double-lock case here, so even when + * doing backlog processing we use the BH locking scheme. + * This is because we cannot sleep with the original spinlock + * held. + */ +int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) +{ + struct sock *rsk; +#ifdef CONFIG_TCP_MD5SIG + /* + * We really want to reject the packet as early as possible + * if: + * o We're expecting an MD5'd packet and this is no MD5 tcp option + * o There is an MD5 option and we're not expecting one + */ + if (tcp_v4_inbound_md5_hash(sk, skb)) + goto discard; +#endif + + if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ + sock_rps_save_rxhash(sk, skb); + if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) { + rsk = sk; + goto reset; + } + return 0; + } + + if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb)) + goto csum_err; + + if (sk->sk_state == TCP_LISTEN) { + struct sock *nsk = tcp_v4_hnd_req(sk, skb); + if (!nsk) + goto discard; + + if (nsk != sk) { + sock_rps_save_rxhash(nsk, skb); + if (tcp_child_process(sk, nsk, skb)) { + rsk = nsk; + goto reset; + } + return 0; + } + } else + sock_rps_save_rxhash(sk, skb); + + if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) { + rsk = sk; + goto reset; + } + return 0; + +reset: + tcp_v4_send_reset(rsk, skb); +discard: + kfree_skb(skb); + /* Be careful here. If this function gets more complicated and + * gcc suffers from register pressure on the x86, sk (in %ebx) + * might be destroyed here. This current version compiles correctly, + * but you have been warned. + */ + return 0; + +csum_err: + TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS); + goto discard; +} +EXPORT_SYMBOL(tcp_v4_do_rcv); + +/* + * From tcp_input.c + */ + +int tcp_v4_rcv(struct sk_buff *skb) +{ + const struct iphdr *iph; + const struct tcphdr *th; + struct sock *sk; + int ret; + struct net *net = dev_net(skb->dev); + + if (skb->pkt_type != PACKET_HOST) + goto discard_it; + + /* Count it even if it's bad */ + TCP_INC_STATS_BH(net, TCP_MIB_INSEGS); + + if (!pskb_may_pull(skb, sizeof(struct tcphdr))) + goto discard_it; + + th = tcp_hdr(skb); + + if (th->doff < sizeof(struct tcphdr) / 4) + goto bad_packet; + if (!pskb_may_pull(skb, th->doff * 4)) + goto discard_it; + + /* An explanation is required here, I think. + * Packet length and doff are validated by header prediction, + * provided case of th->doff==0 is eliminated. + * So, we defer the checks. */ + if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb)) + goto bad_packet; + + th = tcp_hdr(skb); + iph = ip_hdr(skb); + TCP_SKB_CB(skb)->seq = ntohl(th->seq); + TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + + skb->len - th->doff * 4); + TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); + TCP_SKB_CB(skb)->when = 0; + TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph); + TCP_SKB_CB(skb)->sacked = 0; + + sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest); + if (!sk) + goto no_tcp_socket; + +process: + if (sk->sk_state == TCP_TIME_WAIT) + goto do_time_wait; + + if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) { + NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP); + goto discard_and_relse; + } + + if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) + goto discard_and_relse; + nf_reset(skb); + + if (sk_filter(sk, skb)) + goto discard_and_relse; + + skb->dev = NULL; + + bh_lock_sock_nested(sk); + ret = 0; + if (!sock_owned_by_user(sk)) { +#ifdef CONFIG_NET_DMA + struct tcp_sock *tp = tcp_sk(sk); + if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) + tp->ucopy.dma_chan = net_dma_find_channel(); + if (tp->ucopy.dma_chan) + ret = tcp_v4_do_rcv(sk, skb); + else +#endif + { + if (!tcp_prequeue(sk, skb)) + ret = tcp_v4_do_rcv(sk, skb); + } + } else if (unlikely(sk_add_backlog(sk, skb))) { + bh_unlock_sock(sk); + NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP); + goto discard_and_relse; + } + bh_unlock_sock(sk); + + sock_put(sk); + + return ret; + +no_tcp_socket: + if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) + goto discard_it; + + if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) { +bad_packet: + TCP_INC_STATS_BH(net, TCP_MIB_INERRS); + } else { + tcp_v4_send_reset(NULL, skb); + } + +discard_it: + /* Discard frame. */ + kfree_skb(skb); + return 0; + +discard_and_relse: + sock_put(sk); + goto discard_it; + +do_time_wait: + if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { + inet_twsk_put(inet_twsk(sk)); + goto discard_it; + } + + if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) { + TCP_INC_STATS_BH(net, TCP_MIB_INERRS); + inet_twsk_put(inet_twsk(sk)); + goto discard_it; + } + switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) { + case TCP_TW_SYN: { + struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev), + &tcp_hashinfo, + iph->daddr, th->dest, + inet_iif(skb)); + if (sk2) { + inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row); + inet_twsk_put(inet_twsk(sk)); + sk = sk2; + goto process; + } + /* Fall through to ACK */ + } + case TCP_TW_ACK: + tcp_v4_timewait_ack(sk, skb); + break; + case TCP_TW_RST: + goto no_tcp_socket; + case TCP_TW_SUCCESS:; + } + goto discard_it; +} + +struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it) +{ + struct rtable *rt = (struct rtable *) __sk_dst_get(sk); + struct inet_sock *inet = inet_sk(sk); + struct inet_peer *peer; + + if (!rt || + inet->cork.fl.u.ip4.daddr != inet->inet_daddr) { + peer = inet_getpeer_v4(inet->inet_daddr, 1); + *release_it = true; + } else { + if (!rt->peer) + rt_bind_peer(rt, inet->inet_daddr, 1); + peer = rt->peer; + *release_it = false; + } + + return peer; +} +EXPORT_SYMBOL(tcp_v4_get_peer); + +void *tcp_v4_tw_get_peer(struct sock *sk) +{ + const struct inet_timewait_sock *tw = inet_twsk(sk); + + return inet_getpeer_v4(tw->tw_daddr, 1); +} +EXPORT_SYMBOL(tcp_v4_tw_get_peer); + +static struct timewait_sock_ops tcp_timewait_sock_ops = { + .twsk_obj_size = sizeof(struct tcp_timewait_sock), + .twsk_unique = tcp_twsk_unique, + .twsk_destructor= tcp_twsk_destructor, + .twsk_getpeer = tcp_v4_tw_get_peer, +}; + +const struct inet_connection_sock_af_ops ipv4_specific = { + .queue_xmit = ip_queue_xmit, + .send_check = tcp_v4_send_check, + .rebuild_header = inet_sk_rebuild_header, + .conn_request = tcp_v4_conn_request, + .syn_recv_sock = tcp_v4_syn_recv_sock, + .get_peer = tcp_v4_get_peer, + .net_header_len = sizeof(struct iphdr), + .setsockopt = ip_setsockopt, + .getsockopt = ip_getsockopt, + .addr2sockaddr = inet_csk_addr2sockaddr, + .sockaddr_len = sizeof(struct sockaddr_in), + .bind_conflict = inet_csk_bind_conflict, +#ifdef CONFIG_COMPAT + .compat_setsockopt = compat_ip_setsockopt, + .compat_getsockopt = compat_ip_getsockopt, +#endif +}; +EXPORT_SYMBOL(ipv4_specific); + +#ifdef CONFIG_TCP_MD5SIG +static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = { + .md5_lookup = tcp_v4_md5_lookup, + .calc_md5_hash = tcp_v4_md5_hash_skb, + .md5_parse = tcp_v4_parse_md5_keys, +}; +#endif + +/* NOTE: A lot of things set to zero explicitly by call to + * sk_alloc() so need not be done here. + */ +static int tcp_v4_init_sock(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + struct tcp_sock *tp = tcp_sk(sk); + + skb_queue_head_init(&tp->out_of_order_queue); + tcp_init_xmit_timers(sk); + tcp_prequeue_init(tp); + + icsk->icsk_rto = TCP_TIMEOUT_INIT; + tp->mdev = TCP_TIMEOUT_INIT; + + /* So many TCP implementations out there (incorrectly) count the + * initial SYN frame in their delayed-ACK and congestion control + * algorithms that we must have the following bandaid to talk + * efficiently to them. -DaveM + */ + tp->snd_cwnd = TCP_INIT_CWND; + + /* See draft-stevens-tcpca-spec-01 for discussion of the + * initialization of these values. + */ + tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; + tp->snd_cwnd_clamp = ~0; + tp->mss_cache = TCP_MSS_DEFAULT; + + tp->reordering = sysctl_tcp_reordering; + icsk->icsk_ca_ops = &tcp_init_congestion_ops; + + sk->sk_state = TCP_CLOSE; + + sk->sk_write_space = sk_stream_write_space; + sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); + + icsk->icsk_af_ops = &ipv4_specific; + icsk->icsk_sync_mss = tcp_sync_mss; +#ifdef CONFIG_TCP_MD5SIG + tp->af_specific = &tcp_sock_ipv4_specific; +#endif + + /* TCP Cookie Transactions */ + if (sysctl_tcp_cookie_size > 0) { + /* Default, cookies without s_data_payload. */ + tp->cookie_values = + kzalloc(sizeof(*tp->cookie_values), + sk->sk_allocation); + if (tp->cookie_values != NULL) + kref_init(&tp->cookie_values->kref); + } + /* Presumed zeroed, in order of appearance: + * cookie_in_always, cookie_out_never, + * s_data_constant, s_data_in, s_data_out + */ + sk->sk_sndbuf = sysctl_tcp_wmem[1]; + sk->sk_rcvbuf = sysctl_tcp_rmem[1]; + + local_bh_disable(); + sock_update_memcg(sk); + sk_sockets_allocated_inc(sk); + local_bh_enable(); + + return 0; +} + +void tcp_v4_destroy_sock(struct sock *sk) +{ + struct tcp_sock *tp = tcp_sk(sk); + + tcp_clear_xmit_timers(sk); + + tcp_cleanup_congestion_control(sk); + + /* Cleanup up the write buffer. */ + tcp_write_queue_purge(sk); + + /* Cleans up our, hopefully empty, out_of_order_queue. */ + __skb_queue_purge(&tp->out_of_order_queue); + +#ifdef CONFIG_TCP_MD5SIG + /* Clean up the MD5 key list, if any */ + if (tp->md5sig_info) { + tcp_clear_md5_list(sk); + kfree_rcu(tp->md5sig_info, rcu); + tp->md5sig_info = NULL; + } +#endif + +#ifdef CONFIG_NET_DMA + /* Cleans up our sk_async_wait_queue */ + __skb_queue_purge(&sk->sk_async_wait_queue); +#endif + + /* Clean prequeue, it must be empty really */ + __skb_queue_purge(&tp->ucopy.prequeue); + + /* Clean up a referenced TCP bind bucket. */ + if (inet_csk(sk)->icsk_bind_hash) + inet_put_port(sk); + + /* + * If sendmsg cached page exists, toss it. + */ + if (sk->sk_sndmsg_page) { + __free_page(sk->sk_sndmsg_page); + sk->sk_sndmsg_page = NULL; + } + + /* TCP Cookie Transactions */ + if (tp->cookie_values != NULL) { + kref_put(&tp->cookie_values->kref, + tcp_cookie_values_release); + tp->cookie_values = NULL; + } + + sk_sockets_allocated_dec(sk); + sock_release_memcg(sk); +} +EXPORT_SYMBOL(tcp_v4_destroy_sock); + +#ifdef CONFIG_PROC_FS +/* Proc filesystem TCP sock list dumping. */ + +static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head) +{ + return hlist_nulls_empty(head) ? NULL : + list_entry(head->first, struct inet_timewait_sock, tw_node); +} + +static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw) +{ + return !is_a_nulls(tw->tw_node.next) ? + hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL; +} + +/* + * Get next listener socket follow cur. If cur is NULL, get first socket + * starting from bucket given in st->bucket; when st->bucket is zero the + * very first socket in the hash table is returned. + */ +static void *listening_get_next(struct seq_file *seq, void *cur) +{ + struct inet_connection_sock *icsk; + struct hlist_nulls_node *node; + struct sock *sk = cur; + struct inet_listen_hashbucket *ilb; + struct tcp_iter_state *st = seq->private; + struct net *net = seq_file_net(seq); + + if (!sk) { + ilb = &tcp_hashinfo.listening_hash[st->bucket]; + spin_lock_bh(&ilb->lock); + sk = sk_nulls_head(&ilb->head); + st->offset = 0; + goto get_sk; + } + ilb = &tcp_hashinfo.listening_hash[st->bucket]; + ++st->num; + ++st->offset; + + if (st->state == TCP_SEQ_STATE_OPENREQ) { + struct request_sock *req = cur; + + icsk = inet_csk(st->syn_wait_sk); + req = req->dl_next; + while (1) { + while (req) { + if (req->rsk_ops->family == st->family) { + cur = req; + goto out; + } + req = req->dl_next; + } + if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries) + break; +get_req: + req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket]; + } + sk = sk_nulls_next(st->syn_wait_sk); + st->state = TCP_SEQ_STATE_LISTENING; + read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); + } else { + icsk = inet_csk(sk); + read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock); + if (reqsk_queue_len(&icsk->icsk_accept_queue)) + goto start_req; + read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); + sk = sk_nulls_next(sk); + } +get_sk: + sk_nulls_for_each_from(sk, node) { + if (!net_eq(sock_net(sk), net)) + continue; + if (sk->sk_family == st->family) { + cur = sk; + goto out; + } + icsk = inet_csk(sk); + read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock); + if (reqsk_queue_len(&icsk->icsk_accept_queue)) { +start_req: + st->uid = sock_i_uid(sk); + st->syn_wait_sk = sk; + st->state = TCP_SEQ_STATE_OPENREQ; + st->sbucket = 0; + goto get_req; + } + read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); + } + spin_unlock_bh(&ilb->lock); + st->offset = 0; + if (++st->bucket < INET_LHTABLE_SIZE) { + ilb = &tcp_hashinfo.listening_hash[st->bucket]; + spin_lock_bh(&ilb->lock); + sk = sk_nulls_head(&ilb->head); + goto get_sk; + } + cur = NULL; +out: + return cur; +} + +static void *listening_get_idx(struct seq_file *seq, loff_t *pos) +{ + struct tcp_iter_state *st = seq->private; + void *rc; + + st->bucket = 0; + st->offset = 0; + rc = listening_get_next(seq, NULL); + + while (rc && *pos) { + rc = listening_get_next(seq, rc); + --*pos; + } + return rc; +} + +static inline int empty_bucket(struct tcp_iter_state *st) +{ + return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) && + hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain); +} + +/* + * Get first established socket starting from bucket given in st->bucket. + * If st->bucket is zero, the very first socket in the hash is returned. + */ +static void *established_get_first(struct seq_file *seq) +{ + struct tcp_iter_state *st = seq->private; + struct net *net = seq_file_net(seq); + void *rc = NULL; + + st->offset = 0; + for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) { + struct sock *sk; + struct hlist_nulls_node *node; + struct inet_timewait_sock *tw; + spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket); + + /* Lockless fast path for the common case of empty buckets */ + if (empty_bucket(st)) + continue; + + spin_lock_bh(lock); + sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) { + if (sk->sk_family != st->family || + !net_eq(sock_net(sk), net)) { + continue; + } + rc = sk; + goto out; + } + st->state = TCP_SEQ_STATE_TIME_WAIT; + inet_twsk_for_each(tw, node, + &tcp_hashinfo.ehash[st->bucket].twchain) { + if (tw->tw_family != st->family || + !net_eq(twsk_net(tw), net)) { + continue; + } + rc = tw; + goto out; + } + spin_unlock_bh(lock); + st->state = TCP_SEQ_STATE_ESTABLISHED; + } +out: + return rc; +} + +static void *established_get_next(struct seq_file *seq, void *cur) +{ + struct sock *sk = cur; + struct inet_timewait_sock *tw; + struct hlist_nulls_node *node; + struct tcp_iter_state *st = seq->private; + struct net *net = seq_file_net(seq); + + ++st->num; + ++st->offset; + + if (st->state == TCP_SEQ_STATE_TIME_WAIT) { + tw = cur; + tw = tw_next(tw); +get_tw: + while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) { + tw = tw_next(tw); + } + if (tw) { + cur = tw; + goto out; + } + spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); + st->state = TCP_SEQ_STATE_ESTABLISHED; + + /* Look for next non empty bucket */ + st->offset = 0; + while (++st->bucket <= tcp_hashinfo.ehash_mask && + empty_bucket(st)) + ; + if (st->bucket > tcp_hashinfo.ehash_mask) + return NULL; + + spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); + sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain); + } else + sk = sk_nulls_next(sk); + + sk_nulls_for_each_from(sk, node) { + if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) + goto found; + } + + st->state = TCP_SEQ_STATE_TIME_WAIT; + tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain); + goto get_tw; +found: + cur = sk; +out: + return cur; +} + +static void *established_get_idx(struct seq_file *seq, loff_t pos) +{ + struct tcp_iter_state *st = seq->private; + void *rc; + + st->bucket = 0; + rc = established_get_first(seq); + + while (rc && pos) { + rc = established_get_next(seq, rc); + --pos; + } + return rc; +} + +static void *tcp_get_idx(struct seq_file *seq, loff_t pos) +{ + void *rc; + struct tcp_iter_state *st = seq->private; + + st->state = TCP_SEQ_STATE_LISTENING; + rc = listening_get_idx(seq, &pos); + + if (!rc) { + st->state = TCP_SEQ_STATE_ESTABLISHED; + rc = established_get_idx(seq, pos); + } + + return rc; +} + +static void *tcp_seek_last_pos(struct seq_file *seq) +{ + struct tcp_iter_state *st = seq->private; + int offset = st->offset; + int orig_num = st->num; + void *rc = NULL; + + switch (st->state) { + case TCP_SEQ_STATE_OPENREQ: + case TCP_SEQ_STATE_LISTENING: + if (st->bucket >= INET_LHTABLE_SIZE) + break; + st->state = TCP_SEQ_STATE_LISTENING; + rc = listening_get_next(seq, NULL); + while (offset-- && rc) + rc = listening_get_next(seq, rc); + if (rc) + break; + st->bucket = 0; + /* Fallthrough */ + case TCP_SEQ_STATE_ESTABLISHED: + case TCP_SEQ_STATE_TIME_WAIT: + st->state = TCP_SEQ_STATE_ESTABLISHED; + if (st->bucket > tcp_hashinfo.ehash_mask) + break; + rc = established_get_first(seq); + while (offset-- && rc) + rc = established_get_next(seq, rc); + } + + st->num = orig_num; + + return rc; +} + +static void *tcp_seq_start(struct seq_file *seq, loff_t *pos) +{ + struct tcp_iter_state *st = seq->private; + void *rc; + + if (*pos && *pos == st->last_pos) { + rc = tcp_seek_last_pos(seq); + if (rc) + goto out; + } + + st->state = TCP_SEQ_STATE_LISTENING; + st->num = 0; + st->bucket = 0; + st->offset = 0; + rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; + +out: + st->last_pos = *pos; + return rc; +} + +static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct tcp_iter_state *st = seq->private; + void *rc = NULL; + + if (v == SEQ_START_TOKEN) { + rc = tcp_get_idx(seq, 0); + goto out; + } + + switch (st->state) { + case TCP_SEQ_STATE_OPENREQ: + case TCP_SEQ_STATE_LISTENING: + rc = listening_get_next(seq, v); + if (!rc) { + st->state = TCP_SEQ_STATE_ESTABLISHED; + st->bucket = 0; + st->offset = 0; + rc = established_get_first(seq); + } + break; + case TCP_SEQ_STATE_ESTABLISHED: + case TCP_SEQ_STATE_TIME_WAIT: + rc = established_get_next(seq, v); + break; + } +out: + ++*pos; + st->last_pos = *pos; + return rc; +} + +static void tcp_seq_stop(struct seq_file *seq, void *v) +{ + struct tcp_iter_state *st = seq->private; + + switch (st->state) { + case TCP_SEQ_STATE_OPENREQ: + if (v) { + struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk); + read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); + } + case TCP_SEQ_STATE_LISTENING: + if (v != SEQ_START_TOKEN) + spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock); + break; + case TCP_SEQ_STATE_TIME_WAIT: + case TCP_SEQ_STATE_ESTABLISHED: + if (v) + spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); + break; + } +} + +int tcp_seq_open(struct inode *inode, struct file *file) +{ + struct tcp_seq_afinfo *afinfo = PDE(inode)->data; + struct tcp_iter_state *s; + int err; + + err = seq_open_net(inode, file, &afinfo->seq_ops, + sizeof(struct tcp_iter_state)); + if (err < 0) + return err; + + s = ((struct seq_file *)file->private_data)->private; + s->family = afinfo->family; + s->last_pos = 0; + return 0; +} +EXPORT_SYMBOL(tcp_seq_open); + +int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo) +{ + int rc = 0; + struct proc_dir_entry *p; + + afinfo->seq_ops.start = tcp_seq_start; + afinfo->seq_ops.next = tcp_seq_next; + afinfo->seq_ops.stop = tcp_seq_stop; + + p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net, + afinfo->seq_fops, afinfo); + if (!p) + rc = -ENOMEM; + return rc; +} +EXPORT_SYMBOL(tcp_proc_register); + +void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo) +{ + proc_net_remove(net, afinfo->name); +} +EXPORT_SYMBOL(tcp_proc_unregister); + +static void get_openreq4(const struct sock *sk, const struct request_sock *req, + struct seq_file *f, int i, int uid, int *len) +{ + const struct inet_request_sock *ireq = inet_rsk(req); + int ttd = req->expires - jiffies; + + seq_printf(f, "%4d: %08X:%04X %08X:%04X" + " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n", + i, + ireq->loc_addr, + ntohs(inet_sk(sk)->inet_sport), + ireq->rmt_addr, + ntohs(ireq->rmt_port), + TCP_SYN_RECV, + 0, 0, /* could print option size, but that is af dependent. */ + 1, /* timers active (only the expire timer) */ + jiffies_to_clock_t(ttd), + req->retrans, + uid, + 0, /* non standard timer */ + 0, /* open_requests have no inode */ + atomic_read(&sk->sk_refcnt), + req, + len); +} + +static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len) +{ + int timer_active; + unsigned long timer_expires; + const struct tcp_sock *tp = tcp_sk(sk); + const struct inet_connection_sock *icsk = inet_csk(sk); + const struct inet_sock *inet = inet_sk(sk); + __be32 dest = inet->inet_daddr; + __be32 src = inet->inet_rcv_saddr; + __u16 destp = ntohs(inet->inet_dport); + __u16 srcp = ntohs(inet->inet_sport); + int rx_queue; + + if (icsk->icsk_pending == ICSK_TIME_RETRANS) { + timer_active = 1; + timer_expires = icsk->icsk_timeout; + } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { + timer_active = 4; + timer_expires = icsk->icsk_timeout; + } else if (timer_pending(&sk->sk_timer)) { + timer_active = 2; + timer_expires = sk->sk_timer.expires; + } else { + timer_active = 0; + timer_expires = jiffies; + } + + if (sk->sk_state == TCP_LISTEN) + rx_queue = sk->sk_ack_backlog; + else + /* + * because we dont lock socket, we might find a transient negative value + */ + rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0); + + seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " + "%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n", + i, src, srcp, dest, destp, sk->sk_state, + tp->write_seq - tp->snd_una, + rx_queue, + timer_active, + jiffies_to_clock_t(timer_expires - jiffies), + icsk->icsk_retransmits, + sock_i_uid(sk), + icsk->icsk_probes_out, + sock_i_ino(sk), + atomic_read(&sk->sk_refcnt), sk, + jiffies_to_clock_t(icsk->icsk_rto), + jiffies_to_clock_t(icsk->icsk_ack.ato), + (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong, + tp->snd_cwnd, + tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh, + len); +} + +static void get_timewait4_sock(const struct inet_timewait_sock *tw, + struct seq_file *f, int i, int *len) +{ + __be32 dest, src; + __u16 destp, srcp; + int ttd = tw->tw_ttd - jiffies; + + if (ttd < 0) + ttd = 0; + + dest = tw->tw_daddr; + src = tw->tw_rcv_saddr; + destp = ntohs(tw->tw_dport); + srcp = ntohs(tw->tw_sport); + + seq_printf(f, "%4d: %08X:%04X %08X:%04X" + " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n", + i, src, srcp, dest, destp, tw->tw_substate, 0, 0, + 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0, + atomic_read(&tw->tw_refcnt), tw, len); +} + +#define TMPSZ 150 + +static int tcp4_seq_show(struct seq_file *seq, void *v) +{ + struct tcp_iter_state *st; + int len; + + if (v == SEQ_START_TOKEN) { + seq_printf(seq, "%-*s\n", TMPSZ - 1, + " sl local_address rem_address st tx_queue " + "rx_queue tr tm->when retrnsmt uid timeout " + "inode"); + goto out; + } + st = seq->private; + + switch (st->state) { + case TCP_SEQ_STATE_LISTENING: + case TCP_SEQ_STATE_ESTABLISHED: + get_tcp4_sock(v, seq, st->num, &len); + break; + case TCP_SEQ_STATE_OPENREQ: + get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len); + break; + case TCP_SEQ_STATE_TIME_WAIT: + get_timewait4_sock(v, seq, st->num, &len); + break; + } + seq_printf(seq, "%*s\n", TMPSZ - 1 - len, ""); +out: + return 0; +} + +static const struct file_operations tcp_afinfo_seq_fops = { + .owner = THIS_MODULE, + .open = tcp_seq_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_net +}; + +static struct tcp_seq_afinfo tcp4_seq_afinfo = { + .name = "tcp", + .family = AF_INET, + .seq_fops = &tcp_afinfo_seq_fops, + .seq_ops = { + .show = tcp4_seq_show, + }, +}; + +static int __net_init tcp4_proc_init_net(struct net *net) +{ + return tcp_proc_register(net, &tcp4_seq_afinfo); +} + +static void __net_exit tcp4_proc_exit_net(struct net *net) +{ + tcp_proc_unregister(net, &tcp4_seq_afinfo); +} + +static struct pernet_operations tcp4_net_ops = { + .init = tcp4_proc_init_net, + .exit = tcp4_proc_exit_net, +}; + +int __init tcp4_proc_init(void) +{ + return register_pernet_subsys(&tcp4_net_ops); +} + +void tcp4_proc_exit(void) +{ + unregister_pernet_subsys(&tcp4_net_ops); +} +#endif /* CONFIG_PROC_FS */ + +struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb) +{ + const struct iphdr *iph = skb_gro_network_header(skb); + + switch (skb->ip_summed) { + case CHECKSUM_COMPLETE: + if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr, + skb->csum)) { + skb->ip_summed = CHECKSUM_UNNECESSARY; + break; + } + + /* fall through */ + case CHECKSUM_NONE: + NAPI_GRO_CB(skb)->flush = 1; + return NULL; + } + + return tcp_gro_receive(head, skb); +} + +int tcp4_gro_complete(struct sk_buff *skb) +{ + const struct iphdr *iph = ip_hdr(skb); + struct tcphdr *th = tcp_hdr(skb); + + th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb), + iph->saddr, iph->daddr, 0); + skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; + + return tcp_gro_complete(skb); +} + +struct proto tcp_prot = { + .name = "TCP", + .owner = THIS_MODULE, + .close = tcp_close, + .connect = tcp_v4_connect, + .disconnect = tcp_disconnect, + .accept = inet_csk_accept, + .ioctl = tcp_ioctl, + .init = tcp_v4_init_sock, + .destroy = tcp_v4_destroy_sock, + .shutdown = tcp_shutdown, + .setsockopt = tcp_setsockopt, + .getsockopt = tcp_getsockopt, + .recvmsg = tcp_recvmsg, + .sendmsg = tcp_sendmsg, + .sendpage = tcp_sendpage, + .backlog_rcv = tcp_v4_do_rcv, + .hash = inet_hash, + .unhash = inet_unhash, + .get_port = inet_csk_get_port, + .enter_memory_pressure = tcp_enter_memory_pressure, + .sockets_allocated = &tcp_sockets_allocated, + .orphan_count = &tcp_orphan_count, + .memory_allocated = &tcp_memory_allocated, + .memory_pressure = &tcp_memory_pressure, + .sysctl_wmem = sysctl_tcp_wmem, + .sysctl_rmem = sysctl_tcp_rmem, + .max_header = MAX_TCP_HEADER, + .obj_size = sizeof(struct tcp_sock), + .slab_flags = SLAB_DESTROY_BY_RCU, + .twsk_prot = &tcp_timewait_sock_ops, + .rsk_prot = &tcp_request_sock_ops, + .h.hashinfo = &tcp_hashinfo, + .no_autobind = true, +#ifdef CONFIG_COMPAT + .compat_setsockopt = compat_tcp_setsockopt, + .compat_getsockopt = compat_tcp_getsockopt, +#endif +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM + .init_cgroup = tcp_init_cgroup, + .destroy_cgroup = tcp_destroy_cgroup, + .proto_cgroup = tcp_proto_cgroup, +#endif +}; +EXPORT_SYMBOL(tcp_prot); + +static int __net_init tcp_sk_init(struct net *net) +{ + return inet_ctl_sock_create(&net->ipv4.tcp_sock, + PF_INET, SOCK_RAW, IPPROTO_TCP, net); +} + +static void __net_exit tcp_sk_exit(struct net *net) +{ + inet_ctl_sock_destroy(net->ipv4.tcp_sock); +} + +static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list) +{ + inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET); +} + +static struct pernet_operations __net_initdata tcp_sk_ops = { + .init = tcp_sk_init, + .exit = tcp_sk_exit, + .exit_batch = tcp_sk_exit_batch, +}; + +void __init tcp_v4_init(void) +{ + inet_hashinfo_init(&tcp_hashinfo); + if (register_pernet_subsys(&tcp_sk_ops)) + panic("Failed to create the TCP control socket.\n"); +} |