xref: /openbmc/linux/net/ipv4/ip_tunnel_core.c (revision c1d45424)
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 net *net, struct rtable *rt,
50 		  struct sk_buff *skb,
51 		  __be32 src, __be32 dst, __u8 proto,
52 		  __u8 tos, __u8 ttl, __be16 df)
53 {
54 	int pkt_len = skb->len;
55 	struct iphdr *iph;
56 	int err;
57 
58 	nf_reset(skb);
59 	secpath_reset(skb);
60 	skb->rxhash = 0;
61 	skb_dst_drop(skb);
62 	skb_dst_set(skb, &rt->dst);
63 	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
64 
65 	/* Push down and install the IP header. */
66 	__skb_push(skb, sizeof(struct iphdr));
67 	skb_reset_network_header(skb);
68 
69 	iph = ip_hdr(skb);
70 
71 	iph->version	=	4;
72 	iph->ihl	=	sizeof(struct iphdr) >> 2;
73 	iph->frag_off	=	df;
74 	iph->protocol	=	proto;
75 	iph->tos	=	tos;
76 	iph->daddr	=	dst;
77 	iph->saddr	=	src;
78 	iph->ttl	=	ttl;
79 	__ip_select_ident(iph, &rt->dst, (skb_shinfo(skb)->gso_segs ?: 1) - 1);
80 
81 	err = ip_local_out(skb);
82 	if (unlikely(net_xmit_eval(err)))
83 		pkt_len = 0;
84 	return pkt_len;
85 }
86 EXPORT_SYMBOL_GPL(iptunnel_xmit);
87 
88 int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto)
89 {
90 	if (unlikely(!pskb_may_pull(skb, hdr_len)))
91 		return -ENOMEM;
92 
93 	skb_pull_rcsum(skb, hdr_len);
94 
95 	if (inner_proto == htons(ETH_P_TEB)) {
96 		struct ethhdr *eh = (struct ethhdr *)skb->data;
97 
98 		if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
99 			return -ENOMEM;
100 
101 		if (likely(ntohs(eh->h_proto) >= ETH_P_802_3_MIN))
102 			skb->protocol = eh->h_proto;
103 		else
104 			skb->protocol = htons(ETH_P_802_2);
105 
106 	} else {
107 		skb->protocol = inner_proto;
108 	}
109 
110 	nf_reset(skb);
111 	secpath_reset(skb);
112 	if (!skb->l4_rxhash)
113 		skb->rxhash = 0;
114 	skb_dst_drop(skb);
115 	skb->vlan_tci = 0;
116 	skb_set_queue_mapping(skb, 0);
117 	skb->pkt_type = PACKET_HOST;
118 	return 0;
119 }
120 EXPORT_SYMBOL_GPL(iptunnel_pull_header);
121