/* * xfrm4_input.c * * Changes: * YOSHIFUJI Hideaki @USAGI * Split up af-specific portion * Derek Atkins <derek@ihtfp.com> * Add Encapsulation support * */ #include <linux/module.h> #include <linux/string.h> #include <linux/netfilter.h> #include <linux/netfilter_ipv4.h> #include <net/inet_ecn.h> #include <net/ip.h> #include <net/xfrm.h> int xfrm4_rcv(struct sk_buff *skb) { return xfrm4_rcv_encap(skb, 0); } EXPORT_SYMBOL(xfrm4_rcv); static inline void ipip_ecn_decapsulate(struct sk_buff *skb) { struct iphdr *outer_iph = skb->nh.iph; struct iphdr *inner_iph = skb->h.ipiph; if (INET_ECN_is_ce(outer_iph->tos)) IP_ECN_set_ce(inner_iph); } static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, u32 *spi, u32 *seq) { switch (nexthdr) { case IPPROTO_IPIP: *spi = skb->nh.iph->saddr; *seq = 0; return 0; } return xfrm_parse_spi(skb, nexthdr, spi, seq); } #ifdef CONFIG_NETFILTER static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb) { struct iphdr *iph = skb->nh.iph; if (skb->dst == NULL) { if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, skb->dev)) goto drop; } return dst_input(skb); drop: kfree_skb(skb); return NET_RX_DROP; } #endif int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type) { int err; u32 spi, seq; struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH]; struct xfrm_state *x; int xfrm_nr = 0; int decaps = 0; if ((err = xfrm4_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) != 0) goto drop; do { struct iphdr *iph = skb->nh.iph; if (xfrm_nr == XFRM_MAX_DEPTH) goto drop; x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, iph->protocol, AF_INET); if (x == NULL) goto drop; spin_lock(&x->lock); if (unlikely(x->km.state != XFRM_STATE_VALID)) goto drop_unlock; if ((x->encap ? x->encap->encap_type : 0) != encap_type) goto drop_unlock; if (x->props.replay_window && xfrm_replay_check(x, seq)) goto drop_unlock; if (xfrm_state_check_expire(x)) goto drop_unlock; if (x->type->input(x, skb)) goto drop_unlock; /* only the first xfrm gets the encap type */ encap_type = 0; if (x->props.replay_window) xfrm_replay_advance(x, seq); x->curlft.bytes += skb->len; x->curlft.packets++; spin_unlock(&x->lock); xfrm_vec[xfrm_nr++] = x; iph = skb->nh.iph; if (x->props.mode) { if (iph->protocol != IPPROTO_IPIP) goto drop; if (!pskb_may_pull(skb, sizeof(struct iphdr))) goto drop; if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) goto drop; if (x->props.flags & XFRM_STATE_DECAP_DSCP) ipv4_copy_dscp(iph, skb->h.ipiph); if (!(x->props.flags & XFRM_STATE_NOECN)) ipip_ecn_decapsulate(skb); skb->mac.raw = memmove(skb->data - skb->mac_len, skb->mac.raw, skb->mac_len); skb->nh.raw = skb->data; memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options)); decaps = 1; break; } if ((err = xfrm_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) < 0) goto drop; } while (!err); /* Allocate new secpath or COW existing one. */ if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) { struct sec_path *sp; sp = secpath_dup(skb->sp); if (!sp) goto drop; if (skb->sp) secpath_put(skb->sp); skb->sp = sp; } if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH) goto drop; memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec, xfrm_nr * sizeof(xfrm_vec[0])); skb->sp->len += xfrm_nr; nf_reset(skb); if (decaps) { if (!(skb->dev->flags&IFF_LOOPBACK)) { dst_release(skb->dst); skb->dst = NULL; } netif_rx(skb); return 0; } else { #ifdef CONFIG_NETFILTER __skb_push(skb, skb->data - skb->nh.raw); skb->nh.iph->tot_len = htons(skb->len); ip_send_check(skb->nh.iph); NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL, xfrm4_rcv_encap_finish); return 0; #else return -skb->nh.iph->protocol; #endif } drop_unlock: spin_unlock(&x->lock); xfrm_state_put(x); drop: while (--xfrm_nr >= 0) xfrm_state_put(xfrm_vec[xfrm_nr]); kfree_skb(skb); return 0; }