xref: /openbmc/linux/net/ipv4/ip_tunnel_core.c (revision 455f9726)
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 sock *sk, 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, skb_shinfo(skb)->gso_segs ?: 1);
78 
79 	err = ip_local_out_sk(sk, 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 packet is not gso and we are resolving any partial checksum,
139 	 * clear encapsulation flag. This allows setting CHECKSUM_PARTIAL
140 	 * on the outer header without confusing devices that implement
141 	 * NETIF_F_IP_CSUM with encapsulation.
142 	 */
143 	if (csum_help)
144 		skb->encapsulation = 0;
145 
146 	if (skb->ip_summed == CHECKSUM_PARTIAL && csum_help) {
147 		err = skb_checksum_help(skb);
148 		if (unlikely(err))
149 			goto error;
150 	} else if (skb->ip_summed != CHECKSUM_PARTIAL)
151 		skb->ip_summed = CHECKSUM_NONE;
152 
153 	return skb;
154 error:
155 	kfree_skb(skb);
156 	return ERR_PTR(err);
157 }
158 EXPORT_SYMBOL_GPL(iptunnel_handle_offloads);
159 
160 /* Often modified stats are per cpu, other are shared (netdev->stats) */
161 struct rtnl_link_stats64 *ip_tunnel_get_stats64(struct net_device *dev,
162 						struct rtnl_link_stats64 *tot)
163 {
164 	int i;
165 
166 	for_each_possible_cpu(i) {
167 		const struct pcpu_sw_netstats *tstats =
168 						   per_cpu_ptr(dev->tstats, i);
169 		u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
170 		unsigned int start;
171 
172 		do {
173 			start = u64_stats_fetch_begin_irq(&tstats->syncp);
174 			rx_packets = tstats->rx_packets;
175 			tx_packets = tstats->tx_packets;
176 			rx_bytes = tstats->rx_bytes;
177 			tx_bytes = tstats->tx_bytes;
178 		} while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
179 
180 		tot->rx_packets += rx_packets;
181 		tot->tx_packets += tx_packets;
182 		tot->rx_bytes   += rx_bytes;
183 		tot->tx_bytes   += tx_bytes;
184 	}
185 
186 	tot->multicast = dev->stats.multicast;
187 
188 	tot->rx_crc_errors = dev->stats.rx_crc_errors;
189 	tot->rx_fifo_errors = dev->stats.rx_fifo_errors;
190 	tot->rx_length_errors = dev->stats.rx_length_errors;
191 	tot->rx_frame_errors = dev->stats.rx_frame_errors;
192 	tot->rx_errors = dev->stats.rx_errors;
193 
194 	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
195 	tot->tx_carrier_errors = dev->stats.tx_carrier_errors;
196 	tot->tx_dropped = dev->stats.tx_dropped;
197 	tot->tx_aborted_errors = dev->stats.tx_aborted_errors;
198 	tot->tx_errors = dev->stats.tx_errors;
199 
200 	tot->collisions  = dev->stats.collisions;
201 
202 	return tot;
203 }
204 EXPORT_SYMBOL_GPL(ip_tunnel_get_stats64);
205