diff options
Diffstat (limited to 'net/ipv4/xfrm4_mode_beet.c')
| -rw-r--r-- | net/ipv4/xfrm4_mode_beet.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/net/ipv4/xfrm4_mode_beet.c b/net/ipv4/xfrm4_mode_beet.c new file mode 100644 index 00000000..e3db3f91 --- /dev/null +++ b/net/ipv4/xfrm4_mode_beet.c @@ -0,0 +1,156 @@ +/* + * xfrm4_mode_beet.c - BEET mode encapsulation for IPv4. + * + * Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com> + * Miika Komu <miika@iki.fi> + * Herbert Xu <herbert@gondor.apana.org.au> + * Abhinav Pathak <abhinav.pathak@hiit.fi> + * Jeff Ahrenholz <ahrenholz@gmail.com> + */ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/stringify.h> +#include <net/dst.h> +#include <net/ip.h> +#include <net/xfrm.h> + +static void xfrm4_beet_make_header(struct sk_buff *skb) +{ + struct iphdr *iph = ip_hdr(skb); + + iph->ihl = 5; + iph->version = 4; + + iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol; + iph->tos = XFRM_MODE_SKB_CB(skb)->tos; + + iph->id = XFRM_MODE_SKB_CB(skb)->id; + iph->frag_off = XFRM_MODE_SKB_CB(skb)->frag_off; + iph->ttl = XFRM_MODE_SKB_CB(skb)->ttl; +} + +/* Add encapsulation header. + * + * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt. + */ +static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb) +{ + struct ip_beet_phdr *ph; + struct iphdr *top_iph; + int hdrlen, optlen; + + hdrlen = 0; + optlen = XFRM_MODE_SKB_CB(skb)->optlen; + if (unlikely(optlen)) + hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4); + + skb_set_network_header(skb, -x->props.header_len - + hdrlen + (XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph))); + if (x->sel.family != AF_INET6) + skb->network_header += IPV4_BEET_PHMAXLEN; + skb->mac_header = skb->network_header + + offsetof(struct iphdr, protocol); + skb->transport_header = skb->network_header + sizeof(*top_iph); + + xfrm4_beet_make_header(skb); + + ph = (struct ip_beet_phdr *) + __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen); + + top_iph = ip_hdr(skb); + + if (unlikely(optlen)) { + BUG_ON(optlen < 0); + + ph->padlen = 4 - (optlen & 4); + ph->hdrlen = optlen / 8; + ph->nexthdr = top_iph->protocol; + if (ph->padlen) + memset(ph + 1, IPOPT_NOP, ph->padlen); + + top_iph->protocol = IPPROTO_BEETPH; + top_iph->ihl = sizeof(struct iphdr) / 4; + } + + top_iph->saddr = x->props.saddr.a4; + top_iph->daddr = x->id.daddr.a4; + + return 0; +} + +static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb) +{ + struct iphdr *iph; + int optlen = 0; + int err = -EINVAL; + + if (unlikely(XFRM_MODE_SKB_CB(skb)->protocol == IPPROTO_BEETPH)) { + struct ip_beet_phdr *ph; + int phlen; + + if (!pskb_may_pull(skb, sizeof(*ph))) + goto out; + + ph = (struct ip_beet_phdr *)skb->data; + + phlen = sizeof(*ph) + ph->padlen; + optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen); + if (optlen < 0 || optlen & 3 || optlen > 250) + goto out; + + XFRM_MODE_SKB_CB(skb)->protocol = ph->nexthdr; + + if (!pskb_may_pull(skb, phlen)) + goto out; + __skb_pull(skb, phlen); + } + + skb_push(skb, sizeof(*iph)); + skb_reset_network_header(skb); + skb_mac_header_rebuild(skb); + + xfrm4_beet_make_header(skb); + + iph = ip_hdr(skb); + + iph->ihl += optlen / 4; + iph->tot_len = htons(skb->len); + iph->daddr = x->sel.daddr.a4; + iph->saddr = x->sel.saddr.a4; + iph->check = 0; + iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl); + err = 0; +out: + return err; +} + +static struct xfrm_mode xfrm4_beet_mode = { + .input2 = xfrm4_beet_input, + .input = xfrm_prepare_input, + .output2 = xfrm4_beet_output, + .output = xfrm4_prepare_output, + .owner = THIS_MODULE, + .encap = XFRM_MODE_BEET, + .flags = XFRM_MODE_FLAG_TUNNEL, +}; + +static int __init xfrm4_beet_init(void) +{ + return xfrm_register_mode(&xfrm4_beet_mode, AF_INET); +} + +static void __exit xfrm4_beet_exit(void) +{ + int err; + + err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET); + BUG_ON(err); +} + +module_init(xfrm4_beet_init); +module_exit(xfrm4_beet_exit); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET); |