net/ipv4/ip_tunnel_core.c

   1 /*
   2  * Copyright (c) 2013 Nicira, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of version 2 of the GNU General Public
   6  * License as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301, USA
  17  */
  18
  19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  20
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/skbuff.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/in.h>
  26 #include <linux/if_arp.h>
  27 #include <linux/mroute.h>
  28 #include <linux/init.h>
  29 #include <linux/in6.h>
  30 #include <linux/inetdevice.h>
  31 #include <linux/netfilter_ipv4.h>
  32 #include <linux/etherdevice.h>
  33 #include <linux/if_ether.h>
  34 #include <linux/if_vlan.h>
  35
  36 #include <net/ip.h>
  37 #include <net/icmp.h>
  38 #include <net/protocol.h>
  39 #include <net/ip_tunnels.h>
  40 #include <net/arp.h>
  41 #include <net/checksum.h>
  42 #include <net/dsfield.h>
  43 #include <net/inet_ecn.h>
  44 #include <net/xfrm.h>
  45 #include <net/net_namespace.h>
  46 #include <net/netns/generic.h>
  47 #include <net/rtnetlink.h>
  48
  49 int iptunnel_xmit(struct rtable *rt, struct sk_buff *skb,
  50                   __be32 src, __be32 dst, __u8 proto,
  51                   __u8 tos, __u8 ttl, __be16 df, bool xnet)
  52 {
  53         int pkt_len = skb->len;
  54         struct iphdr *iph;
  55         int err;
  56
  57         skb_scrub_packet(skb, xnet);
  58
  59         skb_clear_hash(skb);
  60         skb_dst_set(skb, &rt->dst);
  61         memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
  62
  63         /* Push down and install the IP header. */
  64         skb_push(skb, sizeof(struct iphdr));
  65         skb_reset_network_header(skb);
  66
  67         iph = ip_hdr(skb);
  68
  69         iph->version    =       4;
  70         iph->ihl        =       sizeof(struct iphdr) >> 2;
  71         iph->frag_off   =       df;
  72         iph->protocol   =       proto;
  73         iph->tos        =       tos;
  74         iph->daddr      =       dst;
  75         iph->saddr      =       src;
  76         iph->ttl        =       ttl;
  77         __ip_select_ident(iph, &rt->dst, (skb_shinfo(skb)->gso_segs ?: 1) - 1);
  78
  79         err = ip_local_out(skb);
  80         if (unlikely(net_xmit_eval(err)))
  81                 pkt_len = 0;
  82         return pkt_len;
  83 }
  84 EXPORT_SYMBOL_GPL(iptunnel_xmit);
  85
  86 int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto)
  87 {
  88         if (unlikely(!pskb_may_pull(skb, hdr_len)))
  89                 return -ENOMEM;
  90
  91         skb_pull_rcsum(skb, hdr_len);
  92
  93         if (inner_proto == htons(ETH_P_TEB)) {
  94                 struct ethhdr *eh = (struct ethhdr *)skb->data;
  95
  96                 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
  97                         return -ENOMEM;
  98
  99                 if (likely(ntohs(eh->h_proto) >= ETH_P_802_3_MIN))
 100                         skb->protocol = eh->h_proto;
 101                 else
 102                         skb->protocol = htons(ETH_P_802_2);
 103
 104         } else {
 105                 skb->protocol = inner_proto;
 106         }
 107
 108         nf_reset(skb);
 109         secpath_reset(skb);
 110         skb_clear_hash_if_not_l4(skb);
 111         skb_dst_drop(skb);
 112         skb->vlan_tci = 0;
 113         skb_set_queue_mapping(skb, 0);
 114         skb->pkt_type = PACKET_HOST;
 115         return 0;
 116 }
 117 EXPORT_SYMBOL_GPL(iptunnel_pull_header);
 118
 119 struct sk_buff *iptunnel_handle_offloads(struct sk_buff *skb,
 120                                          bool csum_help,
 121                                          int gso_type_mask)
 122 {
 123         int err;
 124
 125         if (likely(!skb->encapsulation)) {
 126                 skb_reset_inner_headers(skb);
 127                 skb->encapsulation = 1;
 128         }
 129
 130         if (skb_is_gso(skb)) {
 131                 err = skb_unclone(skb, GFP_ATOMIC);
 132                 if (unlikely(err))
 133                         goto error;
 134                 skb_shinfo(skb)->gso_type |= gso_type_mask;
 135                 return skb;
 136         }
 137
 138         if (skb->ip_summed == CHECKSUM_PARTIAL && csum_help) {
 139                 err = skb_checksum_help(skb);
 140                 if (unlikely(err))
 141                         goto error;
 142         } else if (skb->ip_summed != CHECKSUM_PARTIAL)
 143                 skb->ip_summed = CHECKSUM_NONE;
 144
 145         return skb;
 146 error:
 147         kfree_skb(skb);
 148         return ERR_PTR(err);
 149 }
 150 EXPORT_SYMBOL_GPL(iptunnel_handle_offloads);