cregit-Linux how code gets into the kernel

Release 4.11 net/ipv4/ip_output.c

Directory: net/ipv4
/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              The Internet Protocol (IP) output module.
 *
 * Authors:     Ross Biro
 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *              Donald Becker, <becker@super.org>
 *              Alan Cox, <Alan.Cox@linux.org>
 *              Richard Underwood
 *              Stefan Becker, <stefanb@yello.ping.de>
 *              Jorge Cwik, <jorge@laser.satlink.net>
 *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
 *              Hirokazu Takahashi, <taka@valinux.co.jp>
 *
 *      See ip_input.c for original log
 *
 *      Fixes:
 *              Alan Cox        :       Missing nonblock feature in ip_build_xmit.
 *              Mike Kilburn    :       htons() missing in ip_build_xmit.
 *              Bradford Johnson:       Fix faulty handling of some frames when
 *                                      no route is found.
 *              Alexander Demenshin:    Missing sk/skb free in ip_queue_xmit
 *                                      (in case if packet not accepted by
 *                                      output firewall rules)
 *              Mike McLagan    :       Routing by source
 *              Alexey Kuznetsov:       use new route cache
 *              Andi Kleen:             Fix broken PMTU recovery and remove
 *                                      some redundant tests.
 *      Vitaly E. Lavrov        :       Transparent proxy revived after year coma.
 *              Andi Kleen      :       Replace ip_reply with ip_send_reply.
 *              Andi Kleen      :       Split fast and slow ip_build_xmit path
 *                                      for decreased register pressure on x86
 *                                      and more readibility.
 *              Marc Boucher    :       When call_out_firewall returns FW_QUEUE,
 *                                      silently drop skb instead of failing with -EPERM.
 *              Detlev Wengorz  :       Copy protocol for fragments.
 *              Hirokazu Takahashi:     HW checksumming for outgoing UDP
 *                                      datagrams.
 *              Hirokazu Takahashi:     sendfile() on UDP works now.
 */

#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/highmem.h>
#include <linux/slab.h>

#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>

#include <net/snmp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/xfrm.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/arp.h>
#include <net/icmp.h>
#include <net/checksum.h>
#include <net/inetpeer.h>
#include <net/lwtunnel.h>
#include <linux/bpf-cgroup.h>
#include <linux/igmp.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_bridge.h>
#include <linux/netlink.h>
#include <linux/tcp.h>

static int
ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
	    unsigned int mtu,
	    int (*output)(struct net *, struct sock *, struct sk_buff *));

/* Generate a checksum for an outgoing IP datagram. */



void ip_send_check(struct iphdr *iph)
{
	iph->check = 0;
	iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
}

Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)34100.00%1100.00%


Total34100.00%1100.00%




EXPORT_SYMBOL(ip_send_check);




int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct iphdr *iph = ip_hdr(skb);

	iph->tot_len = htons(skb->len);
	ip_send_check(iph);

	/* if egress device is enslaved to an L3 master device pass the
         * skb to its handler for processing
         */
	skb = l3mdev_ip_out(sk, skb);
	if (unlikely(!skb))
		return 0;

	skb->protocol = htons(ETH_P_IP);

	return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT,
		       net, sk, skb, NULL, skb_dst(skb)->dev,
		       dst_output);
}


Contributors
PersonTokensPropCommitsCommitProp
Herbert Xu4746.53%19.09%


David Ahern2120.79%19.09%


David S. Miller109.90%19.09%


Eli Cooper98.91%19.09%


Eric W. Biedermann98.91%436.36%


Eric Dumazet32.97%19.09%


Jan Engelhardt10.99%19.09%


Patrick McHardy10.99%19.09%


Total101100.00%11100.00%






int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	int err;

	err = __ip_local_out(net, sk, skb);
	if (likely(err == 1))
		err = dst_output(net, sk, skb);

	return err;
}

Contributors
PersonTokensPropCommitsCommitProp
Herbert Xu3663.16%111.11%


Eric W. Biedermann1424.56%777.78%


Eric Dumazet712.28%111.11%


Total57100.00%9100.00%




EXPORT_SYMBOL_GPL(ip_local_out);




static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst)
{
	int ttl = inet->uc_ttl;

	if (ttl < 0)
		ttl = ip4_dst_hoplimit(dst);
	return ttl;
}


Contributors
PersonTokensPropCommitsCommitProp
David S. Miller3997.50%266.67%


Arnaldo Carvalho de Melo12.50%133.33%


Total40100.00%3100.00%



/*
 *              Add an ip header to a skbuff and send it out.
 *
 */



int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
			  __be32 saddr, __be32 daddr, struct ip_options_rcu *opt)
{
	struct inet_sock *inet = inet_sk(sk);
	struct rtable *rt = skb_rtable(skb);
	struct net *net = sock_net(sk);
	struct iphdr *iph;

	/* Build the IP header. */
	skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0));
	skb_reset_network_header(skb);
	iph = ip_hdr(skb);
	iph->version  = 4;
	iph->ihl      = 5;
	iph->tos      = inet->tos;
	iph->ttl      = ip_select_ttl(inet, &rt->dst);
	iph->daddr    = (opt && opt->opt.srr ? opt->opt.faddr : daddr);
	iph->saddr    = saddr;
	iph->protocol = sk->sk_protocol;
	if (ip_dont_fragment(sk, &rt->dst)) {
		iph->frag_off = htons(IP_DF);
		iph->id = 0;
	} else {
		iph->frag_off = 0;
		__ip_select_ident(net, iph, 1);
	}

	if (opt && opt->opt.optlen) {
		iph->ihl += opt->opt.optlen>>2;
		ip_options_build(skb, &opt->opt, daddr, rt, 0);
	}

	skb->priority = sk->sk_priority;
	skb->mark = sk->sk_mark;

	/* Send it out. */
	return ip_local_out(net, skb->sk, skb);
}

Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)14149.65%1035.71%


Eric Dumazet5519.37%310.71%


David S. Miller3512.32%310.71%


Arnaldo Carvalho de Melo175.99%414.29%


Eric W. Biedermann175.99%310.71%


Tóth László Attila82.82%13.57%


Alexey Kuznetsov72.46%13.57%


Al Viro20.70%13.57%


Herbert Xu10.35%13.57%


Hannes Frederic Sowa10.35%13.57%


Total284100.00%28100.00%




EXPORT_SYMBOL_GPL(ip_build_and_send_pkt);




static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct dst_entry *dst = skb_dst(skb);
	struct rtable *rt = (struct rtable *)dst;
	struct net_device *dev = dst->dev;
	unsigned int hh_len = LL_RESERVED_SPACE(dev);
	struct neighbour *neigh;
	u32 nexthop;

	if (rt->rt_type == RTN_MULTICAST) {
		IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTMCAST, skb->len);
	} else if (rt->rt_type == RTN_BROADCAST)
		IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTBCAST, skb->len);

	/* Be paranoid, rather than too clever. */
	if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
		struct sk_buff *skb2;

		skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
		if (!skb2) {
			kfree_skb(skb);
			return -ENOMEM;
		}
		if (skb->sk)
			skb_set_owner_w(skb2, skb->sk);
		consume_skb(skb);
		skb = skb2;
	}

	if (lwtunnel_xmit_redirect(dst->lwtstate)) {
		int res = lwtunnel_xmit(skb);

		if (res < 0 || res == LWTUNNEL_XMIT_DONE)
			return res;
	}

	rcu_read_lock_bh();
	nexthop = (__force u32) rt_nexthop(rt, ip_hdr(skb)->daddr);
	neigh = __ipv4_neigh_lookup_noref(dev, nexthop);
	if (unlikely(!neigh))
		neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);
	if (!IS_ERR(neigh)) {
		int res;

		sock_confirm_neigh(skb, neigh);
		res = neigh_output(neigh, skb);

		rcu_read_unlock_bh();
		return res;
	}
	rcu_read_unlock_bh();

	net_dbg_ratelimited("%s: No header cache and no neighbour!\n",
			    __func__);
	kfree_skb(skb);
	return -EINVAL;
}


Contributors
PersonTokensPropCommitsCommitProp
Alexey Kuznetsov8927.38%27.14%


David S. Miller6219.08%621.43%


Linus Torvalds (pre-git)3711.38%310.71%


Mitsuru Chinen3510.77%13.57%


Roopa Prabhu329.85%13.57%


Julian Anastasov206.15%310.71%


Eric Dumazet164.92%310.71%


Neil Horman144.31%13.57%


Eric W. Biedermann72.15%27.14%


Vasiliy Kulikov41.23%13.57%


Joe Perches41.23%13.57%


Pavel Emelyanov20.62%13.57%


Chuck Lever10.31%13.57%


Ian Morris10.31%13.57%


Stephen Hemminger10.31%13.57%


Total325100.00%28100.00%






static int ip_finish_output_gso(struct net *net, struct sock *sk,
				struct sk_buff *skb, unsigned int mtu)
{
	netdev_features_t features;
	struct sk_buff *segs;
	int ret = 0;

	/* common case: seglen is <= mtu
         */
	if (skb_gso_validate_mtu(skb, mtu))
		return ip_finish_output2(net, sk, skb);

	/* Slowpath -  GSO segment length exceeds the egress MTU.
         *
         * This can happen in several cases:
         *  - Forwarding of a TCP GRO skb, when DF flag is not set.
         *  - Forwarding of an skb that arrived on a virtualization interface
         *    (virtio-net/vhost/tap) with TSO/GSO size set by other network
         *    stack.
         *  - Local GSO skb transmitted on an NETIF_F_TSO tunnel stacked over an
         *    interface with a smaller MTU.
         *  - Arriving GRO skb (or GSO skb in a virtualized environment) that is
         *    bridged to a NETIF_F_TSO tunnel stacked over an interface with an
         *    insufficent MTU.
         */
	features = netif_skb_features(skb);
	BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_SGO_CB_OFFSET);
	segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
	if (IS_ERR_OR_NULL(segs)) {
		kfree_skb(skb);
		return -ENOMEM;
	}

	consume_skb(skb);

	do {
		struct sk_buff *nskb = segs->next;
		int err;

		segs->next = NULL;
		err = ip_fragment(net, sk, segs, mtu, ip_finish_output2);

		if (err && ret == 0)
			ret = err;
		segs = nskb;
	} while (segs);

	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Florian Westphal13878.86%333.33%


Konstantin Khlebnikov148.00%111.11%


David S. Miller95.14%111.11%


Eric W. Biedermann95.14%111.11%


Marcelo Ricardo Leitner31.71%111.11%


Lance Richardson21.14%222.22%


Total175100.00%9100.00%






static int ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	unsigned int mtu;
	int ret;

	ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
	if (ret) {
		kfree_skb(skb);
		return ret;
	}

#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
	/* Policy lookup after SNAT yielded a new policy */
	if (skb_dst(skb)->xfrm) {
		IPCB(skb)->flags |= IPSKB_REROUTED;
		return dst_output(net, sk, skb);
	}
#endif
	mtu = ip_skb_dst_mtu(sk, skb);
	if (skb_is_gso(skb))
		return ip_finish_output_gso(net, sk, skb, mtu);

	if (skb->len > mtu || (IPCB(skb)->flags & IPSKB_FRAG_PMTU))
		return ip_fragment(net, sk, skb, mtu, ip_finish_output2);

	return ip_finish_output2(net, sk, skb);
}


Contributors
PersonTokensPropCommitsCommitProp
Patrick McHardy4828.92%317.65%


Florian Westphal4024.10%317.65%


Daniel Mack2615.66%15.88%


Linus Torvalds (pre-git)1911.45%211.76%


Eric W. Biedermann148.43%423.53%


David S. Miller137.83%15.88%


Eric Dumazet31.81%15.88%


Shmulik Ladkani21.20%15.88%


Adrian Bunk10.60%15.88%


Total166100.00%17100.00%






static int ip_mc_finish_output(struct net *net, struct sock *sk,
			       struct sk_buff *skb)
{
	int ret;

	ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
	if (ret) {
		kfree_skb(skb);
		return ret;
	}

	return dev_loopback_xmit(net, sk, skb);
}


Contributors
PersonTokensPropCommitsCommitProp
Daniel Mack57100.00%1100.00%


Total57100.00%1100.00%






int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct rtable *rt = skb_rtable(skb);
	struct net_device *dev = rt->dst.dev;

	/*
         *      If the indicated interface is up and running, send the packet.
         */
	IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);

	skb->dev = dev;
	skb->protocol = htons(ETH_P_IP);

	/*
         *      Multicasts are looped back for other local users
         */

	if (rt->rt_flags&RTCF_MULTICAST) {
		if (sk_mc_loop(sk)
#ifdef CONFIG_IP_MROUTE
		/* Small optimization: do not loopback not local frames,
                   which returned after forwarding; they will be  dropped
                   by ip_mr_input in any case.
                   Note, that local frames are looped back to be delivered
                   to local recipients.

                   This check is duplicated in ip_mr_input at the moment.
                 */
		    &&
		    ((rt->rt_flags & RTCF_LOCAL) ||
		     !(IPCB(skb)->flags & IPSKB_FORWARDED))
#endif
		   ) {
			struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
			if (newskb)
				NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
					net, sk, newskb, NULL, newskb->dev,
					ip_mc_finish_output);
		}

		/* Multicasts with ttl 0 must not go beyond the host */

		if (ip_hdr(skb)->ttl == 0) {
			kfree_skb(skb);
			return 0;
		}
	}

	if (rt->rt_flags&RTCF_BROADCAST) {
		struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
		if (newskb)
			NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
				net, sk, newskb, NULL, newskb->dev,
				ip_mc_finish_output);
	}

	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
			    net, sk, skb, NULL, skb->dev,
			    ip_finish_output,
			    !(IPCB(skb)->flags & IPSKB_REROUTED));
}


Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)17267.19%931.03%


Patrick McHardy249.38%310.34%


Eric W. Biedermann155.86%310.34%


Eric Dumazet83.12%26.90%


David S. Miller83.12%26.90%


Linus Torvalds83.12%13.45%


Neil Horman51.95%13.45%


Alexey Kuznetsov41.56%13.45%


Arnaldo Carvalho de Melo31.17%13.45%


Jan Engelhardt31.17%13.45%


Daniel Mack20.78%13.45%


Pavel Emelyanov10.39%13.45%


Herbert Xu10.39%13.45%


Octavian Purdila10.39%13.45%


Hideaki Yoshifuji / 吉藤英明10.39%13.45%


Total256100.00%29100.00%






int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct net_device *dev = skb_dst(skb)->dev;

	IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);

	skb->dev = dev;
	skb->protocol = htons(ETH_P_IP);

	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
			    net, sk, skb, NULL, dev,
			    ip_finish_output,
			    !(IPCB(skb)->flags & IPSKB_REROUTED));
}


Contributors
PersonTokensPropCommitsCommitProp
Patrick McHardy3842.22%316.67%


Linus Torvalds (pre-git)1516.67%316.67%


Eric W. Biedermann1011.11%316.67%


Eric Dumazet88.89%211.11%


Alexey Kuznetsov77.78%15.56%


Neil Horman55.56%15.56%


David S. Miller22.22%15.56%


Ananda Raju22.22%15.56%


Herbert Xu11.11%15.56%


Pavel Emelyanov11.11%15.56%


Jan Engelhardt11.11%15.56%


Total90100.00%18100.00%



/*
 * copy saddr and daddr, possibly using 64bit load/stores
 * Equivalent to :
 *   iph->saddr = fl4->saddr;
 *   iph->daddr = fl4->daddr;
 */



static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4)
{
	BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) !=
		     offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr));
	memcpy(&iph->saddr, &fl4->saddr,
	       sizeof(fl4->saddr) + sizeof(fl4->daddr));
}


Contributors
PersonTokensPropCommitsCommitProp
Eric Dumazet76100.00%1100.00%


Total76100.00%1100.00%



/* Note: skb->sk can be different from sk, in case of tunnels */



int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)
{
	struct inet_sock *inet = inet_sk(sk);
	struct net *net = sock_net(sk);
	struct ip_options_rcu *inet_opt;
	struct flowi4 *fl4;
	struct rtable *rt;
	struct iphdr *iph;
	int res;

	/* Skip all of this if the packet is already routed,
         * f.e. by something like SCTP.
         */
	rcu_read_lock();
	inet_opt = rcu_dereference(inet->inet_opt);
	fl4 = &fl->u.ip4;
	rt = skb_rtable(skb);
	if (rt)
		goto packet_routed;

	/* Make sure we can route this packet. */
	rt = (struct rtable *)__sk_dst_check(sk, 0);
	if (!rt) {
		__be32 daddr;

		/* Use correct destination address if we have options. */
		daddr = inet->inet_daddr;
		if (inet_opt && inet_opt->opt.srr)
			daddr = inet_opt->opt.faddr;

		/* If this fails, retransmit mechanism of transport layer will
                 * keep trying until route appears or the connection times
                 * itself out.
                 */
		rt = ip_route_output_ports(net, fl4, sk,
					   daddr, inet->inet_saddr,
					   inet->inet_dport,
					   inet->inet_sport,
					   sk->sk_protocol,
					   RT_CONN_FLAGS(sk),
					   sk->sk_bound_dev_if);
		if (IS_ERR(rt))
			goto no_route;
		sk_setup_caps(sk, &rt->dst);
	}
	skb_dst_set_noref(skb, &rt->dst);

packet_routed:
	if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway)
		goto no_route;

	/* OK, we know where to send it, allocate and build IP header. */
	skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0));
	skb_reset_network_header(skb);
	iph = ip_hdr(skb);
	*((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff));
	if (ip_dont_fragment(sk, &rt->dst) && !skb->ignore_df)
		iph->frag_off = htons(IP_DF);
	else
		iph->frag_off = 0;
	iph->ttl      = ip_select_ttl(inet, &rt->dst);
	iph->protocol = sk->sk_protocol;
	ip_copy_addrs(iph, fl4);

	/* Transport layer set skb->h.foo itself. */

	if (inet_opt && inet_opt->opt.optlen) {
		iph->ihl += inet_opt->opt.optlen >> 2;
		ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0);
	}

	ip_select_ident_segs(net, skb, sk,
			     skb_shinfo(skb)->gso_segs ?: 1);

	/* TODO : should we use skb->sk here instead of sk ? */
	skb->priority = sk->sk_priority;
	skb->mark = sk->sk_mark;

	res = ip_local_out(net, sk, skb);
	rcu_read_unlock();
	return res;

no_route:
	rcu_read_unlock();
	IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
	kfree_skb(skb);
	return -EHOSTUNREACH;
}

Contributors
PersonTokensPropCommitsCommitProp
Alexey Kuznetsov21243.80%35.45%


Eric Dumazet7315.08%814.55%


Linus Torvalds (pre-git)7114.67%59.09%


David S. Miller6112.60%1018.18%


Eric W. Biedermann183.72%47.27%


Arnaldo Carvalho de Melo163.31%59.09%


Tóth László Attila81.65%11.82%


Herbert Xu40.83%23.64%


Hideaki Yoshifuji / 吉藤英明30.62%23.64%


Shan Wei20.41%11.82%


Denis V. Lunev20.41%23.64%


Sridhar Samudrala20.41%11.82%


Venkat Yekkirala20.41%11.82%


Al Viro20.41%23.64%


Ian Morris10.21%11.82%


Américo Wang10.21%11.82%


Ansis Atteka10.21%11.82%


Linus Torvalds10.21%11.82%


Atis Elsts10.21%11.82%


Hannes Frederic Sowa10.21%11.82%


Pavel Emelyanov10.21%11.82%


Julian Anastasov10.21%11.82%


Total484100.00%55100.00%




EXPORT_SYMBOL(ip_queue_xmit);




static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
{
	to->pkt_type = from->pkt_type;
	to->priority = from->priority;
	to->protocol = from->protocol;
	skb_dst_drop(to);
	skb_dst_copy(to, from);
	to->dev = from->dev;
	to->mark = from->mark;

	/* Copy the flags to each fragment. */
	IPCB(to)->flags = IPCB(from)->flags;

#ifdef CONFIG_NET_SCHED
	to->tc_index = from->tc_index;
#endif
	nf_copy(to, from);
#if IS_ENABLED(CONFIG_IP_VS)
	to->ipvs_property = from->ipvs_property;
#endif
	skb_copy_secmark(to, from);
}


Contributors
PersonTokensPropCommitsCommitProp
Alexey Kuznetsov8265.08%19.09%


Julian Anastasov1411.11%19.09%


Thomas Graf86.35%19.09%


James Morris75.56%19.09%


Eric Dumazet53.97%218.18%


Patrick McHardy43.17%19.09%


Jozsef Kadlecsik32.38%218.18%


Yasuyuki Kozakai21.59%19.09%


Javier Martinez Canillas10.79%19.09%


Total126100.00%11100.00%






static int ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
		       unsigned int mtu,
		       int (*output)(struct net *, struct sock *, struct sk_buff *))
{
	struct iphdr *iph = ip_hdr(skb);

	if ((iph->frag_off & htons(IP_DF)) == 0)
		return ip_do_fragment(net, sk, skb, output);

	if (unlikely(!skb->ignore_df ||
		     (IPCB(skb)->frag_max_size &&
		      IPCB(skb)->frag_max_size > mtu))) {
		IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
			  htonl(mtu));
		kfree_skb(skb);
		return -EMSGSIZE;
	}

	return ip_do_fragment(net, sk, skb, output);
}


Contributors
PersonTokensPropCommitsCommitProp
Alexey Kuznetsov6743.79%214.29%


Florian Westphal2113.73%214.29%


Patrick McHardy1811.76%17.14%


Eric W. Biedermann149.15%214.29%


Andy Zhou138.50%17.14%


David S. Miller95.88%17.14%


Wei Dong53.27%17.14%


Eric Dumazet21.31%17.14%


Hannes Frederic Sowa21.31%17.14%


Pavel Emelyanov10.65%17.14%


Américo Wang10.65%17.14%


Total153100.00%14100.00%



/*
 *      This IP datagram is too large to be sent in one piece.  Break it up into
 *      smaller pieces (each of size equal to IP header plus
 *      a block of the data of the original IP data part) that will yet fit in a
 *      single device frame, and queue such a frame for sending.
 */




int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
		   int (*output)(struct net *, struct sock *, struct sk_buff *))
{
	struct iphdr *iph;
	int ptr;
	struct sk_buff *skb2;
	unsigned int mtu, hlen, left, len, ll_rs;
	int offset;
	__be16 not_last_frag;
	struct rtable *rt = skb_rtable(skb);
	int err = 0;

	/* for offloaded checksums cleanup checksum before fragmentation */
	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	    (err = skb_checksum_help(skb)))
		goto fail;

	/*
         *      Point into the IP datagram header.
         */

	iph = ip_hdr(skb);

	mtu = ip_skb_dst_mtu(sk, skb);
	if (IPCB(skb)->frag_max_size && IPCB(skb)->frag_max_size < mtu)
		mtu = IPCB(skb)->frag_max_size;

	/*
         *      Setup starting values.
         */

	hlen = iph->ihl * 4;
	mtu = mtu - hlen;	/* Size of data space */
	IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;

	/* When frag_list is given, use it. First, check its validity:
         * some transformers could create wrong frag_list or break existing
         * one, it is not prohibited. In this case fall back to copying.
         *
         * LATER: this step can be merged to real generation of fragments,
         * we can switch to copy when see the first bad fragment.
         */
	if (skb_has_frag_list(skb)) {