cregit-Linux how code gets into the kernel

Release 4.15 net/ipv6/ip6_input.c

Directory: net/ipv6
/*
 *      IPv6 input
 *      Linux INET6 implementation
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>
 *      Ian P. Morris           <I.P.Morris@soton.ac.uk>
 *
 *      Based in linux/net/ipv4/ip_input.c
 *
 *      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.
 */
/* Changes
 *
 *      Mitsuru KANDA @USAGI and
 *      YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
 */

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/in6.h>
#include <linux/icmpv6.h>
#include <linux/mroute6.h>
#include <linux/slab.h>

#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>

#include <net/sock.h>
#include <net/snmp.h>

#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/rawv6.h>
#include <net/ndisc.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/xfrm.h>
#include <net/inet_ecn.h>
#include <net/dst_metadata.h>




int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	void (*edemux)(struct sk_buff *skb);

	/* if ingress device is enslaved to an L3 master device pass the
         * skb to its handler for processing
         */
	skb = l3mdev_ip6_rcv(skb);
	if (!skb)
		return NET_RX_SUCCESS;

	if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
		const struct inet6_protocol *ipprot;

		ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
		if (ipprot && (edemux = READ_ONCE(ipprot->early_demux)))
			edemux(skb);
	}
	if (!skb_valid_dst(skb))
		ip6_route_input(skb);

	return dst_input(skb);
}


Contributors
PersonTokensPropCommitsCommitProp
Eric Dumazet4836.92%218.18%


Linus Torvalds (pre-git)2418.46%19.09%


Subash Abhinov Kasiviswanathan2015.38%19.09%


David Ahern1612.31%19.09%


Holger Eitzenberger64.62%19.09%


David S. Miller53.85%19.09%


Eric W. Biedermann53.85%19.09%


Nikolay Borisov43.08%19.09%


Wei-Chun Chao10.77%19.09%


Hideaki Yoshifuji / 吉藤英明10.77%19.09%


Total130100.00%11100.00%






int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
{
	const struct ipv6hdr *hdr;
	u32 pkt_len;
	struct inet6_dev *idev;
	struct net *net = dev_net(skb->dev);

	if (skb->pkt_type == PACKET_OTHERHOST) {
		kfree_skb(skb);
		return NET_RX_DROP;
	}

	rcu_read_lock();

	idev = __in6_dev_get(skb->dev);

	__IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
	    !idev || unlikely(idev->cnf.disable_ipv6)) {
		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
		goto drop;
	}

	memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));

	/*
         * Store incoming device index. When the packet will
         * be queued, we cannot refer to skb->dev anymore.
         *
         * BTW, when we send a packet for our own local address on a
         * non-loopback interface (e.g. ethX), it is being delivered
         * via the loopback interface (lo) here; skb->dev = loopback_dev.
         * It, however, should be considered as if it is being
         * arrived via the sending interface (ethX), because of the
         * nature of scoping architecture. --yoshfuji
         */
	IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;

	if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
		goto err;

	hdr = ipv6_hdr(skb);

	if (hdr->version != 6)
		goto err;

	__IP6_ADD_STATS(net, idev,
			IPSTATS_MIB_NOECTPKTS +
				(ipv6_get_dsfield(hdr) & INET_ECN_MASK),
			max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
	/*
         * RFC4291 2.5.3
         * The loopback address must not be used as the source address in IPv6
         * packets that are sent outside of a single node. [..]
         * A packet received on an interface with a destination address
         * of loopback must be dropped.
         */
	if ((ipv6_addr_loopback(&hdr->saddr) ||
	     ipv6_addr_loopback(&hdr->daddr)) &&
	     !(dev->flags & IFF_LOOPBACK))
		goto err;

	/* RFC4291 Errata ID: 3480
         * Interface-Local scope spans only a single interface on a
         * node and is useful only for loopback transmission of
         * multicast.  Packets with interface-local scope received
         * from another node must be discarded.
         */
	if (!(skb->pkt_type == PACKET_LOOPBACK ||
	      dev->flags & IFF_LOOPBACK) &&
	    ipv6_addr_is_multicast(&hdr->daddr) &&
	    IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
		goto err;

	/* If enabled, drop unicast packets that were encapsulated in link-layer
         * multicast or broadcast to protected against the so-called "hole-196"
         * attack in 802.11 wireless.
         */
	if (!ipv6_addr_is_multicast(&hdr->daddr) &&
	    (skb->pkt_type == PACKET_BROADCAST ||
	     skb->pkt_type == PACKET_MULTICAST) &&
	    idev->cnf.drop_unicast_in_l2_multicast)
		goto err;

	/* RFC4291 2.7
         * Nodes must not originate a packet to a multicast address whose scope
         * field contains the reserved value 0; if such a packet is received, it
         * must be silently dropped.
         */
	if (ipv6_addr_is_multicast(&hdr->daddr) &&
	    IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
		goto err;

	/*
         * RFC4291 2.7
         * Multicast addresses must not be used as source addresses in IPv6
         * packets or appear in any Routing header.
         */
	if (ipv6_addr_is_multicast(&hdr->saddr))
		goto err;

	skb->transport_header = skb->network_header + sizeof(*hdr);
	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);

	pkt_len = ntohs(hdr->payload_len);

	/* pkt_len may be zero if Jumbo payload option is present */
	if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
		if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
			__IP6_INC_STATS(net,
					idev, IPSTATS_MIB_INTRUNCATEDPKTS);
			goto drop;
		}
		if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
			goto drop;
		}
		hdr = ipv6_hdr(skb);
	}

	if (hdr->nexthdr == NEXTHDR_HOP) {
		if (ipv6_parse_hopopts(skb) < 0) {
			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
			rcu_read_unlock();
			return NET_RX_DROP;
		}
	}

	rcu_read_unlock();

	/* Must drop socket now because of tproxy. */
	skb_orphan(skb);

	return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
		       net, NULL, skb, dev, NULL,
		       ip6_rcv_finish);
err:
	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
drop:
	rcu_read_unlock();
	kfree_skb(skb);
	return NET_RX_DROP;
}


Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)17729.80%714.58%


Hideaki Yoshifuji / 吉藤英明9015.15%714.58%


Hannes Frederic Sowa6310.61%24.17%


Eric Dumazet386.40%510.42%


Johannes Berg355.89%12.08%


Linus Torvalds294.88%12.08%


Denis V. Lunev244.04%12.08%


Patrick McHardy223.70%24.17%


Florian Westphal183.03%12.08%


Guillaume Chazarain162.69%12.08%


Arnaldo Carvalho de Melo142.36%36.25%


Brian Haley142.36%12.08%


Herbert Xu122.02%36.25%


Mitsuru Chinen91.52%12.08%


David S. Miller71.18%24.17%


Shirley Ma61.01%12.08%


Nivedita Singhvi50.84%12.08%


Neil Horman50.84%12.08%


Eric W. Biedermann30.51%24.17%


Mark Smith30.51%12.08%


Wei-Chun Chao10.17%12.08%


Daniel Lezcano10.17%12.08%


Jesper Nilsson10.17%12.08%


Jan Engelhardt10.17%12.08%


Total594100.00%48100.00%



/*
 *      Deliver the packet to the host
 */





static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	const struct inet6_protocol *ipprot;
	struct inet6_dev *idev;
	unsigned int nhoff;
	int nexthdr;
	bool raw;
	bool have_final = false;

	/*
         *      Parse extension headers
         */

	rcu_read_lock();
resubmit:
	idev = ip6_dst_idev(skb_dst(skb));
	if (!pskb_pull(skb, skb_transport_offset(skb)))
		goto discard;
	nhoff = IP6CB(skb)->nhoff;
	nexthdr = skb_network_header(skb)[nhoff];

resubmit_final:
	raw = raw6_local_deliver(skb, nexthdr);
	ipprot = rcu_dereference(inet6_protos[nexthdr]);
	if (ipprot) {
		int ret;

		if (have_final) {
			if (!(ipprot->flags & INET6_PROTO_FINAL)) {
				/* Once we've seen a final protocol don't
                                 * allow encapsulation on any non-final
                                 * ones. This allows foo in UDP encapsulation
                                 * to work.
                                 */
				goto discard;
			}
		} else if (ipprot->flags & INET6_PROTO_FINAL) {
			const struct ipv6hdr *hdr;

			/* Only do this once for first final protocol */
			have_final = true;

			/* Free reference early: we don't need it any more,
                           and it may hold ip_conntrack module loaded
                           indefinitely. */
			nf_reset(skb);

			skb_postpull_rcsum(skb, skb_network_header(skb),
					   skb_network_header_len(skb));
			hdr = ipv6_hdr(skb);
			if (ipv6_addr_is_multicast(&hdr->daddr) &&
			    !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
			    &hdr->saddr) &&
			    !ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
				goto discard;
		}
		if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
		    !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
			goto discard;

		ret = ipprot->handler(skb);
		if (ret > 0) {
			if (ipprot->flags & INET6_PROTO_FINAL) {
				/* Not an extension header, most likely UDP
                                 * encapsulation. Use return value as nexthdr
                                 * protocol not nhoff (which presumably is
                                 * not set by handler).
                                 */
				nexthdr = ret;
				goto resubmit_final;
			} else {
				goto resubmit;
			}
		} else if (ret == 0) {
			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
		}
	} else {
		if (!raw) {
			if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
				__IP6_INC_STATS(net, idev,
						IPSTATS_MIB_INUNKNOWNPROTOS);
				icmpv6_send(skb, ICMPV6_PARAMPROB,
					    ICMPV6_UNK_NEXTHDR, nhoff);
			}
			kfree_skb(skb);
		} else {
			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
			consume_skb(skb);
		}
	}
	rcu_read_unlock();
	return 0;

discard:
	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
	rcu_read_unlock();
	kfree_skb(skb);
	return 0;
}



Contributors
PersonTokensPropCommitsCommitProp
Hideaki Yoshifuji / 吉藤英明7718.29%49.76%


Tom Herbert6114.49%24.88%


Linus Torvalds (pre-git)6014.25%614.63%


David L Stevens4811.40%12.44%


Tom Lendacky337.84%12.44%


David S. Miller307.13%49.76%


Arnaldo Carvalho de Melo153.56%49.76%


Linus Torvalds133.09%12.44%


Patrick McHardy122.85%24.88%


Stephen Hemminger122.85%12.44%


Eric Dumazet102.38%49.76%


Denis V. Lunev81.90%12.44%


Neil Horman81.90%12.44%


Nivedita Singhvi71.66%12.44%


Yasuyuki Kozakai61.43%12.44%


Eric W. Biedermann51.19%12.44%


Ian Morris40.95%12.44%


Pavel Emelyanov40.95%12.44%


Dipankar Sarma30.71%12.44%


Shirley Ma30.71%12.44%


Herbert Xu10.24%12.44%


Alexey Dobriyan10.24%12.44%


Total421100.00%41100.00%






int ip6_input(struct sk_buff *skb)
{
	return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
		       dev_net(skb->dev), NULL, skb, skb->dev, NULL,
		       ip6_input_finish);
}

Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)2670.27%120.00%


Eric W. Biedermann718.92%120.00%


David S. Miller25.41%120.00%


Patrick McHardy12.70%120.00%


Jan Engelhardt12.70%120.00%


Total37100.00%5100.00%




EXPORT_SYMBOL_GPL(ip6_input);




int ip6_mc_input(struct sk_buff *skb)
{
	const struct ipv6hdr *hdr;
	bool deliver;

	__IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
			 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST,
			 skb->len);

	hdr = ipv6_hdr(skb);
	deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);

#ifdef CONFIG_IPV6_MROUTE
	/*
         *      IPv6 multicast router mode is now supported ;)
         */
	if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
	    !(ipv6_addr_type(&hdr->daddr) &
	      (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
	    likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
		/*
                 * Okay, we try to forward - split and duplicate
                 * packets.
                 */
		struct sk_buff *skb2;
		struct inet6_skb_parm *opt = IP6CB(skb);

		/* Check for MLD */
		if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
			/* Check if this is a mld message */
			u8 nexthdr = hdr->nexthdr;
			__be16 frag_off;
			int offset;

			/* Check if the value of Router Alert
                         * is for MLD (0x0000).
                         */
			if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
				deliver = false;

				if (!ipv6_ext_hdr(nexthdr)) {
					/* BUG */
					goto out;
				}
				offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
							  &nexthdr, &frag_off);
				if (offset < 0)
					goto out;

				if (ipv6_is_mld(skb, nexthdr, offset))
					deliver = true;

				goto out;
			}
			/* unknown RA - process it normally */
		}

		if (deliver)
			skb2 = skb_clone(skb, GFP_ATOMIC);
		else {
			skb2 = skb;
			skb = NULL;
		}

		if (skb2) {
			ip6_mr_input(skb2);
		}
	}
out:
#endif
	if (likely(deliver))
		ip6_input(skb);
	else {
		/* discard */
		kfree_skb(skb);
	}

	return 0;
}

Contributors
PersonTokensPropCommitsCommitProp
Hideaki Yoshifuji / 吉藤英明19462.99%626.09%


Linus Torvalds (pre-git)5417.53%417.39%


Thomas Goff134.22%14.35%


Eric Dumazet113.57%417.39%


David L Stevens82.60%28.70%


Denis V. Lunev72.27%14.35%


Jesse Gross61.95%14.35%


Neil Horman51.62%14.35%


Hannes Frederic Sowa41.30%14.35%


Angga30.97%14.35%


Arnaldo Carvalho de Melo30.97%14.35%


Total308100.00%23100.00%




Overall Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)39925.41%88.89%


Hideaki Yoshifuji / 吉藤英明36523.25%1415.56%


Eric Dumazet1107.01%77.78%


Hannes Frederic Sowa674.27%33.33%


Tom Herbert613.89%22.22%


David L Stevens563.57%22.22%


David S. Miller442.80%55.56%


Linus Torvalds422.68%11.11%


Denis V. Lunev392.48%11.11%


Tom Lendacky362.29%11.11%


Patrick McHardy352.23%33.33%


Johannes Berg352.23%11.11%


Arnaldo Carvalho de Melo322.04%66.67%


David Ahern211.34%22.22%


Eric W. Biedermann201.27%33.33%


Subash Abhinov Kasiviswanathan201.27%11.11%


Florian Westphal181.15%11.11%


Neil Horman181.15%22.22%


Guillaume Chazarain161.02%11.11%


Brian Haley140.89%11.11%


Thomas Goff130.83%11.11%


Herbert Xu130.83%33.33%


Nivedita Singhvi120.76%11.11%


Stephen Hemminger120.76%11.11%


Mitsuru Chinen90.57%11.11%


Shirley Ma90.57%11.11%


Jesse Gross60.38%11.11%


Holger Eitzenberger60.38%11.11%


Yasuyuki Kozakai60.38%11.11%


Ian Morris50.32%22.22%


Wei-Chun Chao50.32%11.11%


Nikolay Borisov40.25%11.11%


Pavel Emelyanov40.25%11.11%


Angga30.19%11.11%


Dipankar Sarma30.19%11.11%


Tejun Heo30.19%11.11%


Mark Smith30.19%11.11%


Jan Engelhardt20.13%11.11%


Jesper Nilsson10.06%11.11%


Daniel Lezcano10.06%11.11%


Adrian Bunk10.06%11.11%


Alexey Dobriyan10.06%11.11%


Total1570100.00%90100.00%


Directory: net/ipv6



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