diff options
Diffstat (limited to 'net/ipv4/xfrm4_mode_beet.c')
| -rw-r--r-- | net/ipv4/xfrm4_mode_beet.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/net/ipv4/xfrm4_mode_beet.c b/net/ipv4/xfrm4_mode_beet.c new file mode 100644 index 00000000000..89cf59ea7bb --- /dev/null +++ b/net/ipv4/xfrm4_mode_beet.c @@ -0,0 +1,139 @@ +/* + * 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> + +/* Add encapsulation header. + * + * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt. + * The following fields in it shall be filled in by x->type->output: + * tot_len + * check + * + * On exit, skb->h will be set to the start of the payload to be processed + * by x->type->output and skb->nh will be set to the top IP header. + */ +static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb) +{ + struct iphdr *iph, *top_iph = NULL; + int hdrlen, optlen; + + iph = skb->nh.iph; + skb->h.ipiph = iph; + + hdrlen = 0; + optlen = iph->ihl * 4 - sizeof(*iph); + if (unlikely(optlen)) + hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4); + + skb->nh.raw = skb_push(skb, x->props.header_len + hdrlen); + top_iph = skb->nh.iph; + hdrlen = iph->ihl * 4 - optlen; + skb->h.raw += hdrlen; + + memmove(top_iph, iph, hdrlen); + if (unlikely(optlen)) { + struct ip_beet_phdr *ph; + + BUG_ON(optlen < 0); + + ph = (struct ip_beet_phdr *)skb->h.raw; + ph->padlen = 4 - (optlen & 4); + ph->hdrlen = (optlen + ph->padlen + sizeof(*ph)) / 8; + ph->nexthdr = top_iph->protocol; + + 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 = skb->nh.iph; + int phlen = 0; + int optlen = 0; + __u8 ph_nexthdr = 0, protocol = 0; + int err = -EINVAL; + + protocol = iph->protocol; + + if (unlikely(iph->protocol == IPPROTO_BEETPH)) { + struct ip_beet_phdr *ph = (struct ip_beet_phdr*)(iph + 1); + + if (!pskb_may_pull(skb, sizeof(*ph))) + goto out; + + phlen = ph->hdrlen * 8; + optlen = phlen - ph->padlen - sizeof(*ph); + if (optlen < 0 || optlen & 3 || optlen > 250) + goto out; + + if (!pskb_may_pull(skb, phlen)) + goto out; + + ph_nexthdr = ph->nexthdr; + } + + skb_push(skb, sizeof(*iph) - phlen + optlen); + memmove(skb->data, skb->nh.raw, sizeof(*iph)); + skb->nh.raw = skb->data; + + iph = skb->nh.iph; + iph->ihl = (sizeof(*iph) + optlen) / 4; + iph->tot_len = htons(skb->len); + iph->daddr = x->sel.daddr.a4; + iph->saddr = x->sel.saddr.a4; + if (ph_nexthdr) + iph->protocol = ph_nexthdr; + else + iph->protocol = protocol; + iph->check = 0; + iph->check = ip_fast_csum(skb->nh.raw, iph->ihl); + err = 0; +out: + return err; +} + +static struct xfrm_mode xfrm4_beet_mode = { + .input = xfrm4_beet_input, + .output = xfrm4_beet_output, + .owner = THIS_MODULE, + .encap = XFRM_MODE_BEET, +}; + +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); |