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net/ipv4/xfrm4_mode_tunnel.c
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81f7e3824 Initial Release, ... |
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/* * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4. * * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au> */ #include <linux/gfp.h> #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/inet_ecn.h> #include <net/ip.h> #include <net/xfrm.h> static inline void ipip_ecn_decapsulate(struct sk_buff *skb) { struct iphdr *inner_iph = ipip_hdr(skb); if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos)) IP_ECN_set_ce(inner_iph); } /* Add encapsulation header. * * The top IP header will be constructed per RFC 2401. */ static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb) { struct dst_entry *dst = skb_dst(skb); struct iphdr *top_iph; int flags; skb_set_inner_network_header(skb, skb_network_offset(skb)); skb_set_inner_transport_header(skb, skb_transport_offset(skb)); skb_set_network_header(skb, -x->props.header_len); skb->mac_header = skb->network_header + offsetof(struct iphdr, protocol); skb->transport_header = skb->network_header + sizeof(*top_iph); top_iph = ip_hdr(skb); top_iph->ihl = 5; top_iph->version = 4; top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family); /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */ if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP) top_iph->tos = 0; else top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos; top_iph->tos = INET_ECN_encapsulate(top_iph->tos, XFRM_MODE_SKB_CB(skb)->tos); flags = x->props.flags; if (flags & XFRM_STATE_NOECN) IP_ECN_clear(top_iph); top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ? 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF)); top_iph->ttl = ip4_dst_hoplimit(dst->child); top_iph->saddr = x->props.saddr.a4; top_iph->daddr = x->id.daddr.a4; ip_select_ident(dev_net(dst->dev), skb, NULL); return 0; } static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) { int err = -EINVAL; if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP) goto out; if (!pskb_may_pull(skb, sizeof(struct iphdr))) goto out; err = skb_unclone(skb, GFP_ATOMIC); if (err) goto out; if (x->props.flags & XFRM_STATE_DECAP_DSCP) ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb)); if (!(x->props.flags & XFRM_STATE_NOECN)) ipip_ecn_decapsulate(skb); skb_reset_network_header(skb); skb_mac_header_rebuild(skb); err = 0; out: return err; } static struct sk_buff *xfrm4_mode_tunnel_gso_segment(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features) { __skb_push(skb, skb->mac_len); return skb_mac_gso_segment(skb, features); } static void xfrm4_mode_tunnel_xmit(struct xfrm_state *x, struct sk_buff *skb) { struct xfrm_offload *xo = xfrm_offload(skb); if (xo->flags & XFRM_GSO_SEGMENT) { skb->network_header = skb->network_header - x->props.header_len; skb->transport_header = skb->network_header + sizeof(struct iphdr); } skb_reset_mac_len(skb); pskb_pull(skb, skb->mac_len + x->props.header_len); } static struct xfrm_mode xfrm4_tunnel_mode = { .input2 = xfrm4_mode_tunnel_input, .input = xfrm_prepare_input, .output2 = xfrm4_mode_tunnel_output, .output = xfrm4_prepare_output, .gso_segment = xfrm4_mode_tunnel_gso_segment, .xmit = xfrm4_mode_tunnel_xmit, .owner = THIS_MODULE, .encap = XFRM_MODE_TUNNEL, .flags = XFRM_MODE_FLAG_TUNNEL, }; static int __init xfrm4_mode_tunnel_init(void) { return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET); } static void __exit xfrm4_mode_tunnel_exit(void) { int err; err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET); BUG_ON(err); } module_init(xfrm4_mode_tunnel_init); module_exit(xfrm4_mode_tunnel_exit); MODULE_LICENSE("GPL"); MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL); |