cregit-Linux how code gets into the kernel

Release 4.14 net/ipv4/ip_gre.c

Directory: net/ipv4
/*
 *      Linux NET3:     GRE over IP protocol decoder.
 *
 *      Authors: Alexey Kuznetsov (kuznet@ms2.inr.ac.ru)
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 *
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/in.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/if_arp.h>
#include <linux/if_vlan.h>
#include <linux/init.h>
#include <linux/in6.h>
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#include <linux/netfilter_ipv4.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>

#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/protocol.h>
#include <net/ip_tunnels.h>
#include <net/arp.h>
#include <net/checksum.h>
#include <net/dsfield.h>
#include <net/inet_ecn.h>
#include <net/xfrm.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/rtnetlink.h>
#include <net/gre.h>
#include <net/dst_metadata.h>
#include <net/erspan.h>

/*
   Problems & solutions
   --------------------

   1. The most important issue is detecting local dead loops.
   They would cause complete host lockup in transmit, which
   would be "resolved" by stack overflow or, if queueing is enabled,
   with infinite looping in net_bh.

   We cannot track such dead loops during route installation,
   it is infeasible task. The most general solutions would be
   to keep skb->encapsulation counter (sort of local ttl),
   and silently drop packet when it expires. It is a good
   solution, but it supposes maintaining new variable in ALL
   skb, even if no tunneling is used.

   Current solution: xmit_recursion breaks dead loops. This is a percpu
   counter, since when we enter the first ndo_xmit(), cpu migration is
   forbidden. We force an exit if this counter reaches RECURSION_LIMIT

   2. Networking dead loops would not kill routers, but would really
   kill network. IP hop limit plays role of "t->recursion" in this case,
   if we copy it from packet being encapsulated to upper header.
   It is very good solution, but it introduces two problems:

   - Routing protocols, using packets with ttl=1 (OSPF, RIP2),
     do not work over tunnels.
   - traceroute does not work. I planned to relay ICMP from tunnel,
     so that this problem would be solved and traceroute output
     would even more informative. This idea appeared to be wrong:
     only Linux complies to rfc1812 now (yes, guys, Linux is the only
     true router now :-)), all routers (at least, in neighbourhood of mine)
     return only 8 bytes of payload. It is the end.

   Hence, if we want that OSPF worked or traceroute said something reasonable,
   we should search for another solution.

   One of them is to parse packet trying to detect inner encapsulation
   made by our node. It is difficult or even impossible, especially,
   taking into account fragmentation. TO be short, ttl is not solution at all.

   Current solution: The solution was UNEXPECTEDLY SIMPLE.
   We force DF flag on tunnels with preconfigured hop limit,
   that is ALL. :-) Well, it does not remove the problem completely,
   but exponential growth of network traffic is changed to linear
   (branches, that exceed pmtu are pruned) and tunnel mtu
   rapidly degrades to value <68, where looping stops.
   Yes, it is not good if there exists a router in the loop,
   which does not force DF, even when encapsulating packets have DF set.
   But it is not our problem! Nobody could accuse us, we made
   all that we could make. Even if it is your gated who injected
   fatal route to network, even if it were you who configured
   fatal static route: you are innocent. :-)

   Alexey Kuznetsov.
 */


static bool log_ecn_error = true;
module_param(log_ecn_error, bool, 0644);
MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");


static struct rtnl_link_ops ipgre_link_ops __read_mostly;
static int ipgre_tunnel_init(struct net_device *dev);
static void erspan_build_header(struct sk_buff *skb,
				__be32 id, u32 index, bool truncate);


static unsigned int ipgre_net_id __read_mostly;

static unsigned int gre_tap_net_id __read_mostly;

static unsigned int erspan_net_id __read_mostly;




static void ipgre_err(struct sk_buff *skb, u32 info,
		      const struct tnl_ptk_info *tpi)
{

	/* All the routers (except for Linux) return only
           8 bytes of packet payload. It means, that precise relaying of
           ICMP in the real Internet is absolutely infeasible.

           Moreover, Cisco "wise men" put GRE key to the third word
           in GRE header. It makes impossible maintaining even soft
           state for keyed GRE tunnels with enabled checksum. Tell
           them "thank you".

           Well, I wonder, rfc1812 was written by Cisco employee,
           what the hell these idiots break standards established
           by themselves???
           */
	struct net *net = dev_net(skb->dev);
	struct ip_tunnel_net *itn;
	const struct iphdr *iph;
	const int type = icmp_hdr(skb)->type;
	const int code = icmp_hdr(skb)->code;
	unsigned int data_len = 0;
	struct ip_tunnel *t;

	switch (type) {
	default:
	case ICMP_PARAMETERPROB:
		return;

	case ICMP_DEST_UNREACH:
		switch (code) {
		case ICMP_SR_FAILED:
		case ICMP_PORT_UNREACH:
			/* Impossible event. */
			return;
		default:
			/* All others are translated to HOST_UNREACH.
                           rfc2003 contains "deep thoughts" about NET_UNREACH,
                           I believe they are just ether pollution. --ANK
                         */
			break;
		}
		break;

	case ICMP_TIME_EXCEEDED:
		if (code != ICMP_EXC_TTL)
			return;
		data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
		break;

	case ICMP_REDIRECT:
		break;
	}

	if (tpi->proto == htons(ETH_P_TEB))
		itn = net_generic(net, gre_tap_net_id);
	else
		itn = net_generic(net, ipgre_net_id);

	iph = (const struct iphdr *)(icmp_hdr(skb) + 1);
	t = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
			     iph->daddr, iph->saddr, tpi->key);

	if (!t)
		return;

#if IS_ENABLED(CONFIG_IPV6)
       if (tpi->proto == htons(ETH_P_IPV6) &&
           !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4 + tpi->hdr_len,
				       type, data_len))
               return;
#endif

	if (t->parms.iph.daddr == 0 ||
	    ipv4_is_multicast(t->parms.iph.daddr))
		return;

	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
		return;

	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
		t->err_count++;
	else
		t->err_count = 1;
	t->err_time = jiffies;
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar17552.24%317.65%


Eric Dumazet7422.09%423.53%


Linus Torvalds (pre-git)6720.00%211.76%


Duan Jiong72.09%15.88%


Pavel Emelyanov41.19%211.76%


Linus Torvalds20.60%15.88%


Stephen Hemminger20.60%15.88%


Patrick McHardy20.60%15.88%


Ian Morris10.30%15.88%


Hideaki Yoshifuji / 吉藤英明10.30%15.88%


Total335100.00%17100.00%






static void gre_err(struct sk_buff *skb, u32 info)
{
	/* All the routers (except for Linux) return only
         * 8 bytes of packet payload. It means, that precise relaying of
         * ICMP in the real Internet is absolutely infeasible.
         *
         * Moreover, Cisco "wise men" put GRE key to the third word
         * in GRE header. It makes impossible maintaining even soft
         * state for keyed
         * GRE tunnels with enabled checksum. Tell them "thank you".
         *
         * Well, I wonder, rfc1812 was written by Cisco employee,
         * what the hell these idiots break standards established
         * by themselves???
         */

	const struct iphdr *iph = (struct iphdr *)skb->data;
	const int type = icmp_hdr(skb)->type;
	const int code = icmp_hdr(skb)->code;
	struct tnl_ptk_info tpi;
	bool csum_err = false;

	if (gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP),
			     iph->ihl * 4) < 0) {
		if (!csum_err)		/* ignore csum errors. */
			return;
	}

	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
				 skb->dev->ifindex, 0, IPPROTO_GRE, 0);
		return;
	}
	if (type == ICMP_REDIRECT) {
		ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0,
			      IPPROTO_GRE, 0);
		return;
	}

	ipgre_err(skb, info, &tpi);
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar14883.15%116.67%


Eric Dumazet2111.80%116.67%


Haishuang Yan52.81%116.67%


Jiri Benc21.12%116.67%


Linus Torvalds (pre-git)10.56%116.67%


Tom Herbert10.56%116.67%


Total178100.00%6100.00%






static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
		      int gre_hdr_len)
{
	struct net *net = dev_net(skb->dev);
	struct metadata_dst *tun_dst = NULL;
	struct ip_tunnel_net *itn;
	struct ip_tunnel *tunnel;
	struct erspanhdr *ershdr;
	const struct iphdr *iph;
	__be32 index;
	int len;

	itn = net_generic(net, erspan_net_id);
	len = gre_hdr_len + sizeof(*ershdr);

	if (unlikely(!pskb_may_pull(skb, len)))
		return -ENOMEM;

	iph = ip_hdr(skb);
	ershdr = (struct erspanhdr *)(skb->data + gre_hdr_len);

	/* The original GRE header does not have key field,
         * Use ERSPAN 10-bit session ID as key.
         */
	tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
	index = ershdr->md.index;
	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
				  tpi->flags | TUNNEL_KEY,
				  iph->saddr, iph->daddr, tpi->key);

	if (tunnel) {
		if (__iptunnel_pull_header(skb,
					   gre_hdr_len + sizeof(*ershdr),
					   htons(ETH_P_TEB),
					   false, false) < 0)
			goto drop;

		if (tunnel->collect_md) {
			struct ip_tunnel_info *info;
			struct erspan_metadata *md;
			__be64 tun_id;
			__be16 flags;

			tpi->flags |= TUNNEL_KEY;
			flags = tpi->flags;
			tun_id = key32_to_tunnel_id(tpi->key);

			tun_dst = ip_tun_rx_dst(skb, flags,
						tun_id, sizeof(*md));
			if (!tun_dst)
				return PACKET_REJECT;

			md = ip_tunnel_info_opts(&tun_dst->u.tun_info);
			if (!md)
				return PACKET_REJECT;

			md->index = index;
			info = &tun_dst->u.tun_info;
			info->key.tun_flags |= TUNNEL_ERSPAN_OPT;
			info->options_len = sizeof(*md);
		} else {
			tunnel->index = ntohl(index);
		}

		skb_reset_mac_header(skb);
		ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
		return PACKET_RCVD;
	}
drop:
	kfree_skb(skb);
	return PACKET_RCVD;
}


Contributors
PersonTokensPropCommitsCommitProp
William Tu37598.68%266.67%


Xin Long51.32%133.33%


Total380100.00%3100.00%






static int __ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
		       struct ip_tunnel_net *itn, int hdr_len, bool raw_proto)
{
	struct metadata_dst *tun_dst = NULL;
	const struct iphdr *iph;
	struct ip_tunnel *tunnel;

	iph = ip_hdr(skb);
	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
				  iph->saddr, iph->daddr, tpi->key);

	if (tunnel) {
		if (__iptunnel_pull_header(skb, hdr_len, tpi->proto,
					   raw_proto, false) < 0)
			goto drop;

		if (tunnel->dev->type != ARPHRD_NONE)
			skb_pop_mac_header(skb);
		else
			skb_reset_mac_header(skb);
		if (tunnel->collect_md) {
			__be16 flags;
			__be64 tun_id;

			flags = tpi->flags & (TUNNEL_CSUM | TUNNEL_KEY);
			tun_id = key32_to_tunnel_id(tpi->key);
			tun_dst = ip_tun_rx_dst(skb, flags, tun_id, 0);
			if (!tun_dst)
				return PACKET_REJECT;
		}

		ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
		return PACKET_RCVD;
	}
	return PACKET_NEXT;

drop:
	kfree_skb(skb);
	return PACKET_RCVD;
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar10950.46%430.77%


Jiri Benc6027.78%323.08%


Linus Torvalds (pre-git)3616.67%17.69%


Timo Teräs73.24%215.38%


David S. Miller20.93%17.69%


Stephen Hemminger10.46%17.69%


Amir Vadai10.46%17.69%


Total216100.00%13100.00%






static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
		     int hdr_len)
{
	struct net *net = dev_net(skb->dev);
	struct ip_tunnel_net *itn;
	int res;

	if (tpi->proto == htons(ETH_P_TEB))
		itn = net_generic(net, gre_tap_net_id);
	else
		itn = net_generic(net, ipgre_net_id);

	res = __ipgre_rcv(skb, tpi, itn, hdr_len, false);
	if (res == PACKET_NEXT && tpi->proto == htons(ETH_P_TEB)) {
		/* ipgre tunnels in collect metadata mode should receive
                 * also ETH_P_TEB traffic.
                 */
		itn = net_generic(net, ipgre_net_id);
		res = __ipgre_rcv(skb, tpi, itn, hdr_len, true);
	}
	return res;
}


Contributors
PersonTokensPropCommitsCommitProp
Jiri Benc12999.23%266.67%


Timo Teräs10.77%133.33%


Total130100.00%3100.00%






static int gre_rcv(struct sk_buff *skb)
{
	struct tnl_ptk_info tpi;
	bool csum_err = false;
	int hdr_len;

#ifdef CONFIG_NET_IPGRE_BROADCAST
	if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {
		/* Looped back packet, drop it! */
		if (rt_is_output_route(skb_rtable(skb)))
			goto drop;
	}
#endif

	hdr_len = gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP), 0);
	if (hdr_len < 0)
		goto drop;

	if (unlikely(tpi.proto == htons(ETH_P_ERSPAN))) {
		if (erspan_rcv(skb, &tpi, hdr_len) == PACKET_RCVD)
			return 0;
	}

	if (ipgre_rcv(skb, &tpi, hdr_len) == PACKET_RCVD)
		return 0;

	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
drop:
	kfree_skb(skb);
	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar10265.38%114.29%


William Tu3522.44%114.29%


Jiri Benc85.13%228.57%


Haishuang Yan53.21%114.29%


Tom Herbert42.56%114.29%


Eric Dumazet21.28%114.29%


Total156100.00%7100.00%






static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
		       const struct iphdr *tnl_params,
		       __be16 proto)
{
	struct ip_tunnel *tunnel = netdev_priv(dev);

	if (tunnel->parms.o_flags & TUNNEL_SEQ)
		tunnel->o_seqno++;

	/* Push GRE header. */
	gre_build_header(skb, tunnel->tun_hlen,
			 tunnel->parms.o_flags, proto, tunnel->parms.o_key,
			 htonl(tunnel->o_seqno));

	ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar9398.94%150.00%


Tom Herbert11.06%150.00%


Total94100.00%2100.00%






static int gre_handle_offloads(struct sk_buff *skb, bool csum)
{
	return iptunnel_handle_offloads(skb, csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar2596.15%150.00%


Alexander Duyck13.85%150.00%


Total26100.00%2100.00%






static struct rtable *gre_get_rt(struct sk_buff *skb,
				 struct net_device *dev,
				 struct flowi4 *fl,
				 const struct ip_tunnel_key *key)
{
	struct net *net = dev_net(dev);

	memset(fl, 0, sizeof(*fl));
	fl->daddr = key->u.ipv4.dst;
	fl->saddr = key->u.ipv4.src;
	fl->flowi4_tos = RT_TOS(key->tos);
	fl->flowi4_mark = skb->mark;
	fl->flowi4_proto = IPPROTO_GRE;

	return ip_route_output_key(net, fl);
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar109100.00%2100.00%


Total109100.00%2100.00%






static struct rtable *prepare_fb_xmit(struct sk_buff *skb,
				      struct net_device *dev,
				      struct flowi4 *fl,
				      int tunnel_hlen)
{
	struct ip_tunnel_info *tun_info;
	const struct ip_tunnel_key *key;
	struct rtable *rt = NULL;
	int min_headroom;
	bool use_cache;
	int err;

	tun_info = skb_tunnel_info(skb);
	key = &tun_info->key;
	use_cache = ip_tunnel_dst_cache_usable(skb, tun_info);

	if (use_cache)
		rt = dst_cache_get_ip4(&tun_info->dst_cache, &fl->saddr);
	if (!rt) {
		rt = gre_get_rt(skb, dev, fl, key);
		if (IS_ERR(rt))
			goto err_free_skb;
		if (use_cache)
			dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
					  fl->saddr);
	}

	min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
			+ tunnel_hlen + sizeof(struct iphdr);
	if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
		int head_delta = SKB_DATA_ALIGN(min_headroom -
						skb_headroom(skb) +
						16);
		err = pskb_expand_head(skb, max_t(int, head_delta, 0),
				       0, GFP_ATOMIC);
		if (unlikely(err))
			goto err_free_rt;
	}
	return rt;

err_free_rt:
	ip_rt_put(rt);
err_free_skb:
	kfree_skb(skb);
	dev->stats.tx_dropped++;
	return NULL;
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar15559.85%228.57%


William Tu4115.83%114.29%


Paolo Abeni4115.83%114.29%


Daniel Borkmann207.72%114.29%


Jiri Benc10.39%114.29%


Eric Dumazet10.39%114.29%


Total259100.00%7100.00%






static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
			__be16 proto)
{
	struct ip_tunnel_info *tun_info;
	const struct ip_tunnel_key *key;
	struct rtable *rt = NULL;
	struct flowi4 fl;
	int tunnel_hlen;
	__be16 df, flags;

	tun_info = skb_tunnel_info(skb);
	if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
		     ip_tunnel_info_af(tun_info) != AF_INET))
		goto err_free_skb;

	key = &tun_info->key;
	tunnel_hlen = gre_calc_hlen(key->tun_flags);

	rt = prepare_fb_xmit(skb, dev, &fl, tunnel_hlen);
	if (!rt)
		return;

	/* Push Tunnel header. */
	if (gre_handle_offloads(skb, !!(tun_info->key.tun_flags & TUNNEL_CSUM)))
		goto err_free_rt;

	flags = tun_info->key.tun_flags & (TUNNEL_CSUM | TUNNEL_KEY);
	gre_build_header(skb, tunnel_hlen, flags, proto,
			 tunnel_id_to_key32(tun_info->key.tun_id), 0);

	df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;

	iptunnel_xmit(skb->sk, rt, skb, fl.saddr, key->u.ipv4.dst, IPPROTO_GRE,
		      key->tos, key->ttl, df, false);
	return;

err_free_rt:
	ip_rt_put(rt);
err_free_skb:
	kfree_skb(skb);
	dev->stats.tx_dropped++;
}


Contributors
PersonTokensPropCommitsCommitProp
William Tu11846.83%16.67%


Pravin B Shelar10742.46%213.33%


Jiri Benc83.17%320.00%


Linus Torvalds (pre-git)62.38%16.67%


Tom Herbert41.59%213.33%


Eric Dumazet31.19%213.33%


Pavel Emelyanov20.79%16.67%


Alexander Duyck20.79%16.67%


Amir Vadai10.40%16.67%


Nicolas Dichtel10.40%16.67%


Total252100.00%15100.00%






static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,
			   __be16 proto)
{
	struct ip_tunnel *tunnel = netdev_priv(dev);
	struct ip_tunnel_info *tun_info;
	const struct ip_tunnel_key *key;
	struct erspan_metadata *md;
	struct rtable *rt = NULL;
	bool truncate = false;
	struct flowi4 fl;
	int tunnel_hlen;
	__be16 df;

	tun_info = skb_tunnel_info(skb);
	if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
		     ip_tunnel_info_af(tun_info) != AF_INET))
		goto err_free_skb;

	key = &tun_info->key;

	/* ERSPAN has fixed 8 byte GRE header */
	tunnel_hlen = 8 + sizeof(struct erspanhdr);

	rt = prepare_fb_xmit(skb, dev, &fl, tunnel_hlen);
	if (!rt)
		return;

	if (gre_handle_offloads(skb, false))
		goto err_free_rt;

	if (skb->len > dev->mtu) {
		pskb_trim(skb, dev->mtu);
		truncate = true;
	}

	md = ip_tunnel_info_opts(tun_info);
	if (!md)
		goto err_free_rt;

	erspan_build_header(skb, tunnel_id_to_key32(key->tun_id),
			    ntohl(md->index), truncate);

	gre_build_header(skb, 8, TUNNEL_SEQ,
			 htons(ETH_P_ERSPAN), 0, htonl(tunnel->o_seqno++));

	df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;

	iptunnel_xmit(skb->sk, rt, skb, fl.saddr, key->u.ipv4.dst, IPPROTO_GRE,
		      key->tos, key->ttl, df, false);
	return;

err_free_rt:
	ip_rt_put(rt);
err_free_skb:
	kfree_skb(skb);
	dev->stats.tx_dropped++;
}


Contributors
PersonTokensPropCommitsCommitProp
William Tu310100.00%1100.00%


Total310100.00%1100.00%






static int gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
{
	struct ip_tunnel_info *info = skb_tunnel_info(skb);
	struct rtable *rt;
	struct flowi4 fl4;

	if (ip_tunnel_info_af(info) != AF_INET)
		return -EINVAL;

	rt = gre_get_rt(skb, dev, &fl4, &info->key);
	if (IS_ERR(rt))
		return PTR_ERR(rt);

	ip_rt_put(rt);
	info->key.u.ipv4.src = fl4.saddr;
	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar100100.00%1100.00%


Total100100.00%1100.00%






static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
			      struct net_device *dev)
{
	struct ip_tunnel *tunnel = netdev_priv(dev);
	const struct iphdr *tnl_params;

	if (tunnel->collect_md) {
		gre_fb_xmit(skb, dev, skb->protocol);
		return NETDEV_TX_OK;
	}

	if (dev->header_ops) {
		/* Need space for new headers */
		if (skb_cow_head(skb, dev->needed_headroom -
				      (tunnel->hlen + sizeof(struct iphdr))))
			goto free_skb;

		tnl_params = (const struct iphdr *)skb->data;

		/* Pull skb since ip_tunnel_xmit() needs skb->data pointing
                 * to gre header.
                 */
		skb_pull(skb, tunnel->hlen + sizeof(struct iphdr));
		skb_reset_mac_header(skb);
	} else {
		if (skb_cow_head(skb, dev->needed_headroom))
			goto free_skb;

		tnl_params = &tunnel->parms.iph;
	}

	if (gre_handle_offloads(skb, !!(tunnel->parms.o_flags & TUNNEL_CSUM)))
		goto free_skb;

	__gre_xmit(skb, dev, tnl_params, skb->protocol);
	return NETDEV_TX_OK;

free_skb:
	kfree_skb(skb);
	dev->stats.tx_dropped++;
	return NETDEV_TX_OK;
}


Contributors
PersonTokensPropCommitsCommitProp
Pravin B Shelar12260.10%218.18%


Linus Torvalds (pre-git)2914.29%218.18%


Timo Teräs2411.82%19.09%


Stephen Hemminger136.40%19.09%


Ville Nuorvala62.96%19.09%


Jiri Benc41.97%19.09%


Alexander Duyck31.48%19.09%


Eric Dumazet20.99%218.18%


Total203100.00%11100.00%






static inline u8 tos_to_cos(u8 tos)
{
	u8 dscp, cos;

	dscp = tos >> 2;
	cos = dscp >> 3;
	return cos;
}


Contributors
PersonTokensPropCommitsCommitProp
William Tu2996.67%150.00%


Pravin B Shelar13.33%150.00%


Total30100.00%2100.00%






static void erspan_build_header(struct sk_buff *skb,
				__be32 id, u32 index, bool truncate)
{
	struct iphdr *iphdr = ip_hdr(skb);
	struct ethhdr *eth = eth_hdr(skb);
	enum erspan_encap_type enc_type;
	struct erspanhdr *ershdr;
	struct qtag_prefix {
		__be16 eth_type;
		__be16 tci;
	} *qp;
	u16 vlan_tci = 0;

	enc_type = ERSPAN_ENCAP_NOVLAN;

	/* If mirrored packet has vlan tag, extract tci and
         *  perserve vlan header in the mirrored frame.
         */
	if (eth->h_proto == htons(ETH_P_8021Q)) {