Release 4.11 net/dccp/ipv6.c

/*
 *      DCCP over IPv6
 *      Linux INET6 implementation
 *
 *      Based on net/dccp6/ipv6.c
 *
 *      Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
 *
 *      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.
 */

#include <linux/module.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/xfrm.h>

#include <net/addrconf.h>
#include <net/inet_common.h>
#include <net/inet_hashtables.h>
#include <net/inet_sock.h>
#include <net/inet6_connection_sock.h>
#include <net/inet6_hashtables.h>
#include <net/ip6_route.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/ip6_checksum.h>
#include <net/xfrm.h>
#include <net/secure_seq.h>

#include "dccp.h"
#include "ipv6.h"
#include "feat.h"

/* The per-net dccp.v6_ctl_sk is used for sending RSTs and ACKs */


static const struct inet_connection_sock_af_ops dccp_ipv6_mapped;

static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops;

/* add pseudo-header to DCCP checksum stored in skb->csum */


static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
				      const struct in6_addr *saddr,
				      const struct in6_addr *daddr)
{
	return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum);
}

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Arnaldo Carvalho de Melo
31
73.81%
1
25.00%
Gerrit Renker
8
19.05%
1
25.00%
Eric Dumazet
2
4.76%
1
25.00%
Al Viro
1
2.38%
1
25.00%
Total
42
100.00%
4
100.00%



static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct dccp_hdr *dh = dccp_hdr(skb);

	dccp_csum_outgoing(skb);
	dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr);
}

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Gerrit Renker
59
96.72%
1
50.00%
Eric Dumazet
2
3.28%
1
50.00%
Total
61
100.00%
2
100.00%



static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
{
	return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
					     ipv6_hdr(skb)->saddr.s6_addr32,
					     dccp_hdr(skb)->dccph_dport,
					     dccp_hdr(skb)->dccph_sport     );

}

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Arnaldo Carvalho de Melo
39
81.25%
2
40.00%
Gerrit Renker
8
16.67%
2
40.00%
David S. Miller
1
2.08%
1
20.00%
Total
48
100.00%
5
100.00%



static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
			u8 type, u8 code, int offset, __be32 info)
{
	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
	const struct dccp_hdr *dh;
	struct dccp_sock *dp;
	struct ipv6_pinfo *np;
	struct sock *sk;
	int err;
	__u64 seq;
	struct net *net = dev_net(skb->dev);

	/* Only need dccph_dport & dccph_sport which are the first
         * 4 bytes in dccp header.
         * Our caller (icmpv6_notify()) already pulled 8 bytes for us.
         */
	BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
	BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
	dh = (struct dccp_hdr *)(skb->data + offset);

	sk = __inet6_lookup_established(net, &dccp_hashinfo,
					&hdr->daddr, dh->dccph_dport,
					&hdr->saddr, ntohs(dh->dccph_sport),
					inet6_iif(skb));

	if (!sk) {
		__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
				  ICMP6_MIB_INERRORS);
		return;
	}

	if (sk->sk_state == DCCP_TIME_WAIT) {
		inet_twsk_put(inet_twsk(sk));
		return;
	}
	seq = dccp_hdr_seq(dh);
	if (sk->sk_state == DCCP_NEW_SYN_RECV)
		return dccp_req_err(sk, seq);

	bh_lock_sock(sk);
	if (sock_owned_by_user(sk))
		__NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);

	if (sk->sk_state == DCCP_CLOSED)
		goto out;

	dp = dccp_sk(sk);
	if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
	    !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
		__NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
		goto out;
	}

	np = inet6_sk(sk);

	if (type == NDISC_REDIRECT) {
		if (!sock_owned_by_user(sk)) {
			struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);

			if (dst)
				dst->ops->redirect(dst, sk, skb);
		}
		goto out;
	}

	if (type == ICMPV6_PKT_TOOBIG) {
		struct dst_entry *dst = NULL;

		if (!ip6_sk_accept_pmtu(sk))
			goto out;

		if (sock_owned_by_user(sk))
			goto out;
		if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
			goto out;

		dst = inet6_csk_update_pmtu(sk, ntohl(info));
		if (!dst)
			goto out;

		if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
			dccp_sync_mss(sk, dst_mtu(dst));
		goto out;
	}

	icmpv6_err_convert(type, code, &err);

	/* Might be for an request_sock */
	switch (sk->sk_state) {
	case DCCP_REQUESTING:
	case DCCP_RESPOND:  /* Cannot happen.
                               It can, it SYNs are crossed. --ANK */
		if (!sock_owned_by_user(sk)) {
			__DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
			sk->sk_err = err;
			/*
                         * Wake people up to see the error
                         * (see connect in sock.c)
                         */
			sk->sk_error_report(sk);
			dccp_done(sk);
		} else
			sk->sk_err_soft = err;
		goto out;
	}

	if (!sock_owned_by_user(sk) && np->recverr) {
		sk->sk_err = err;
		sk->sk_error_report(sk);
	} else
		sk->sk_err_soft = err;

out:
	bh_unlock_sock(sk);
	sock_put(sk);
}


Contributors
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Gerrit Renker
218
37.46%
1
4.00%
Arnaldo Carvalho de Melo
141
24.23%
3
12.00%
Eric Dumazet
68
11.68%
6
24.00%
Wei Yongjun
62
10.65%
2
8.00%
David S. Miller
45
7.73%
4
16.00%
Pavel Emelyanov
20
3.44%
4
16.00%
Hannes Frederic Sowa
11
1.89%
1
4.00%
Jon Maxwell
10
1.72%
1
4.00%
Duan Jiong
3
0.52%
1
4.00%
Brian Haley
2
0.34%
1
4.00%
Denis V. Lunev
2
0.34%
1
4.00%
Total
582
100.00%
25
100.00%



static int dccp_v6_send_response(const struct sock *sk, struct request_sock *req)
{
	struct inet_request_sock *ireq = inet_rsk(req);
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct sk_buff *skb;
	struct in6_addr *final_p, final;
	struct flowi6 fl6;
	int err = -1;
	struct dst_entry *dst;

	memset(&fl6, 0, sizeof(fl6));
	fl6.flowi6_proto = IPPROTO_DCCP;
	fl6.daddr = ireq->ir_v6_rmt_addr;
	fl6.saddr = ireq->ir_v6_loc_addr;
	fl6.flowlabel = 0;
	fl6.flowi6_oif = ireq->ir_iif;
	fl6.fl6_dport = ireq->ir_rmt_port;
	fl6.fl6_sport = htons(ireq->ir_num);
	security_req_classify_flow(req, flowi6_to_flowi(&fl6));


	rcu_read_lock();
	final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
	rcu_read_unlock();

	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
	if (IS_ERR(dst)) {
		err = PTR_ERR(dst);
		dst = NULL;
		goto done;
	}

	skb = dccp_make_response(sk, dst, req);
	if (skb != NULL) {
		struct dccp_hdr *dh = dccp_hdr(skb);
		struct ipv6_txoptions *opt;

		dh->dccph_checksum = dccp_v6_csum_finish(skb,
							 &ireq->ir_v6_loc_addr,
							 &ireq->ir_v6_rmt_addr);
		fl6.daddr = ireq->ir_v6_rmt_addr;
		rcu_read_lock();
		opt = ireq->ipv6_opt;
		if (!opt)
			opt = rcu_dereference(np->opt);
		err = ip6_xmit(sk, skb, &fl6, sk->sk_mark, opt, np->tclass);
		rcu_read_unlock();
		err = net_xmit_eval(err);
	}

done:
	dst_release(dst);
	return err;
}

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Gerrit Renker
100
30.49%
3
14.29%
Arnaldo Carvalho de Melo
95
28.96%
2
9.52%
David S. Miller
43
13.11%
3
14.29%
Eric Dumazet
42
12.80%
5
23.81%
Huw Davies
25
7.62%
1
4.76%
Arnaud Ebalard
6
1.83%
1
4.76%
Denis V. Lunev
5
1.52%
1
4.76%
Pablo Neira Ayuso
4
1.22%
1
4.76%
Alexey Dobriyan
3
0.91%
1
4.76%
Hideaki Yoshifuji / 吉藤英明
2
0.61%
1
4.76%
Li RongQing
2
0.61%
1
4.76%
Venkat Yekkirala
1
0.30%
1
4.76%
Total
328
100.00%
21
100.00%



static void dccp_v6_reqsk_destructor(struct request_sock *req)
{
	dccp_feat_list_purge(&dccp_rsk(req)->dreq_featneg);
	kfree(inet_rsk(req)->ipv6_opt);
	kfree_skb(inet_rsk(req)->pktopts);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Gerrit Renker
25
59.52%
2
40.00%
Huw Davies
10
23.81%
1
20.00%
Arnaldo Carvalho de Melo
6
14.29%
1
20.00%
Eric Dumazet
1
2.38%
1
20.00%
Total
42
100.00%
5
100.00%



static void dccp_v6_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb)
{
	const struct ipv6hdr *rxip6h;
	struct sk_buff *skb;
	struct flowi6 fl6;
	struct net *net = dev_net(skb_dst(rxskb)->dev);
	struct sock *ctl_sk = net->dccp.v6_ctl_sk;
	struct dst_entry *dst;

	if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
		return;

	if (!ipv6_unicast_destination(rxskb))
		return;

	skb = dccp_ctl_make_reset(ctl_sk, rxskb);
	if (skb == NULL)
		return;

	rxip6h = ipv6_hdr(rxskb);
	dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr,
							    &rxip6h->daddr);

	memset(&fl6, 0, sizeof(fl6));
	fl6.daddr = rxip6h->saddr;
	fl6.saddr = rxip6h->daddr;

	fl6.flowi6_proto = IPPROTO_DCCP;
	fl6.flowi6_oif = inet6_iif(rxskb);
	fl6.fl6_dport = dccp_hdr(skb)->dccph_dport;
	fl6.fl6_sport = dccp_hdr(skb)->dccph_sport;
	security_skb_classify_flow(rxskb, flowi6_to_flowi(&fl6));

	/* sk = NULL, but it is safe for now. RST socket required. */
	dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
	if (!IS_ERR(dst)) {
		skb_dst_set(skb, dst);
		ip6_xmit(ctl_sk, skb, &fl6, 0, NULL, 0);
		DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
		DCCP_INC_STATS(DCCP_MIB_OUTRSTS);
		return;
	}

	kfree_skb(skb);
}

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Gerrit Renker
115
42.91%
4
20.00%
Arnaldo Carvalho de Melo
60
22.39%
2
10.00%
David S. Miller
32
11.94%
3
15.00%
Pavel Emelyanov
26
9.70%
2
10.00%
Eric Dumazet
21
7.84%
5
25.00%
Venkat Yekkirala
5
1.87%
1
5.00%
Hideaki Yoshifuji / 吉藤英明
5
1.87%
1
5.00%
Pablo Neira Ayuso
2
0.75%
1
5.00%
Alexey Dobriyan
2
0.75%
1
5.00%
Total
268
100.00%
20
100.00%


static struct request_sock_ops dccp6_request_sock_ops = {
	.family		= AF_INET6,
	.obj_size	= sizeof(struct dccp6_request_sock),
	.rtx_syn_ack	= dccp_v6_send_response,
	.send_ack	= dccp_reqsk_send_ack,
	.destructor	= dccp_v6_reqsk_destructor,
	.send_reset	= dccp_v6_ctl_send_reset,
	.syn_ack_timeout = dccp_syn_ack_timeout,
};



static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
{
	struct request_sock *req;
	struct dccp_request_sock *dreq;
	struct inet_request_sock *ireq;
	struct ipv6_pinfo *np = inet6_sk(sk);
	const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);

	if (skb->protocol == htons(ETH_P_IP))
		return dccp_v4_conn_request(sk, skb);

	if (!ipv6_unicast_destination(skb))
		return 0;	/* discard, don't send a reset here */

	if (dccp_bad_service_code(sk, service)) {
		dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
		goto drop;
	}
	/*
         * There are no SYN attacks on IPv6, yet...
         */
	dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
	if (inet_csk_reqsk_queue_is_full(sk))
		goto drop;

	if (sk_acceptq_is_full(sk))
		goto drop;

	req = inet_reqsk_alloc(&dccp6_request_sock_ops, sk, true);
	if (req == NULL)
		goto drop;

	if (dccp_reqsk_init(req, dccp_sk(sk), skb))
		goto drop_and_free;

	dreq = dccp_rsk(req);
	if (dccp_parse_options(sk, dreq, skb))
		goto drop_and_free;

	if (security_inet_conn_request(sk, skb, req))
		goto drop_and_free;

	ireq = inet_rsk(req);
	ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
	ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
	ireq->ireq_family = AF_INET6;

	if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) ||
	    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
	    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
		atomic_inc(&skb->users);
		ireq->pktopts = skb;
	}
	ireq->ir_iif = sk->sk_bound_dev_if;

	/* So that link locals have meaning */
	if (!sk->sk_bound_dev_if &&
	    ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
		ireq->ir_iif = inet6_iif(skb);

	/*
         * Step 3: Process LISTEN state
         *
         *   Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
         *
         * Setting S.SWL/S.SWH to is deferred to dccp_create_openreq_child().
         */
	dreq->dreq_isr	   = dcb->dccpd_seq;
	dreq->dreq_gsr     = dreq->dreq_isr;
	dreq->dreq_iss	   = dccp_v6_init_sequence(skb);
	dreq->dreq_gss     = dreq->dreq_iss;
	dreq->dreq_service = service;

	if (dccp_v6_send_response(sk, req))
		goto drop_and_free;

	inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
	return 0;

drop_and_free:
	reqsk_free(req);
drop:
	__DCCP_INC_STATS(DCCP_MIB_ATTEMPTFAILS);
	return -1;
}

Contributors
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Gerrit Renker
278
65.11%
5
25.00%
Arnaldo Carvalho de Melo
93
21.78%
4
20.00%
Eric Dumazet
32
7.49%
7
35.00%
Samuel Jero
17
3.98%
1
5.00%
Venkat Yekkirala
4
0.94%
1
5.00%
Alexey Dobriyan
2
0.47%
1
5.00%
Octavian Purdila
1
0.23%
1
5.00%
Total
427
100.00%
20
100.00%



static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
					      struct sk_buff *skb,
					      struct request_sock *req,
					      struct dst_entry *dst,
					      struct request_sock *req_unhash,
					      bool *own_req)
{
	struct inet_request_sock *ireq = inet_rsk(req);
	struct ipv6_pinfo *newnp;
	const struct ipv6_pinfo *np = inet6_sk(sk);
	struct ipv6_txoptions *opt;
	struct inet_sock *newinet;
	struct dccp6_sock *newdp6;
	struct sock *newsk;

	if (skb->protocol == htons(ETH_P_IP)) {
		/*
                 *      v6 mapped
                 */
		newsk = dccp_v4_request_recv_sock(sk, skb, req, dst,
						  req_unhash, own_req);
		if (newsk == NULL)
			return NULL;

		newdp6 = (struct dccp6_sock *)newsk;
		newinet = inet_sk(newsk);
		newinet->pinet6 = &newdp6->inet6;
		newnp = inet6_sk(newsk);

		memcpy(newnp, np, sizeof(struct ipv6_pinfo));

		newnp->saddr = newsk->sk_v6_rcv_saddr;

		inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
		newsk->sk_backlog_rcv = dccp_v4_do_rcv;
		newnp->pktoptions  = NULL;
		newnp->opt	   = NULL;
		newnp->mcast_oif   = inet6_iif(skb);
		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;

		/*
                 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
                 * here, dccp_create_openreq_child now does this for us, see the comment in
                 * that function for the gory details. -acme
                 */

		/* It is tricky place. Until this moment IPv4 tcp
                   worked with IPv6 icsk.icsk_af_ops.
                   Sync it now.
                 */
		dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);

		return newsk;
	}


	if (sk_acceptq_is_full(sk))
		goto out_overflow;

	if (!dst) {
		struct flowi6 fl6;

		dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_DCCP);
		if (!dst)
			goto out;
	}

	newsk = dccp_create_openreq_child(sk, req, skb);
	if (newsk == NULL)
		goto out_nonewsk;

	/*
         * No need to charge this sock to the relevant IPv6 refcnt debug socks
         * count here, dccp_create_openreq_child now does this for us, see the
         * comment in that function for the gory details. -acme
         */

	ip6_dst_store(newsk, dst, NULL, NULL);
	newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
						      NETIF_F_TSO);
	newdp6 = (struct dccp6_sock *)newsk;
	newinet = inet_sk(newsk);
	newinet->pinet6 = &newdp6->inet6;
	newnp = inet6_sk(newsk);

	memcpy(newnp, np, sizeof(struct ipv6_pinfo));

	newsk->sk_v6_daddr	= ireq->ir_v6_rmt_addr;
	newnp->saddr		= ireq->ir_v6_loc_addr;
	newsk->sk_v6_rcv_saddr	= ireq->ir_v6_loc_addr;
	newsk->sk_bound_dev_if	= ireq->ir_iif;

	/* Now IPv6 options...

           First: no IPv4 options.
         */
	newinet->inet_opt = NULL;

	/* Clone RX bits */
	newnp->rxopt.all = np->rxopt.all;

	newnp->pktoptions = NULL;
	newnp->opt	  = NULL;
	newnp->mcast_oif  = inet6_iif(skb);
	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;

	/*
         * Clone native IPv6 options from listening socket (if any)
         *
         * Yes, keeping reference count would be much more clever, but we make
         * one more one thing there: reattach optmem to newsk.
         */
	opt = ireq->ipv6_opt;
	if (!opt)
		opt = rcu_dereference(np->opt);
	if (opt) {
		opt = ipv6_dup_options(newsk, opt);
		RCU_INIT_POINTER(newnp->opt, opt);
	}
	inet_csk(newsk)->icsk_ext_hdr_len = 0;
	if (opt)
		inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
						    opt->opt_flen;

	dccp_sync_mss(newsk, dst_mtu(dst));

	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;

	if (__inet_inherit_port(sk, newsk) < 0) {
		inet_csk_prepare_forced_close(newsk);
		dccp_done(newsk);
		goto out;
	}
	*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
	/* Clone pktoptions received with SYN, if we own the req */
	if (*own_req && ireq->pktopts) {
		newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
		consume_skb(ireq->pktopts);
		ireq->pktopts = NULL;
		if (newnp->pktoptions)
			skb_set_owner_r(newnp->pktoptions, newsk);
	}

	return newsk;

out_overflow:
	__NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
out_nonewsk:
	dst_release(dst);
out:
	__NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENDROPS);
	return NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Gerrit Renker
271
39.22%
1
3.85%
Arnaldo Carvalho de Melo
219
31.69%
2
7.69%
Eric Dumazet
137
19.83%
13
50.00%
Balazs Scheidler
25
3.62%
1
3.85%
Huw Davies
11
1.59%
1
3.85%
Pavel Emelyanov
10
1.45%
1
3.85%
Christoph Paasch
6
0.87%
1
3.85%
David S. Miller
5
0.72%
2
7.69%
Alexey Dobriyan
3
0.43%
1
3.85%
Li RongQing
2
0.29%
1
3.85%
Hideaki Yoshifuji / 吉藤英明
1
0.14%
1
3.85%
Brian Haley
1
0.14%
1
3.85%
Total
691
100.00%
26
100.00%

/* The socket must have it's spinlock held when we get
 * here.
 *
 * We have a potential double-lock case here, so even when
 * doing backlog processing we use the BH locking scheme.
 * This is because we cannot sleep with the original spinlock
 * held.
 */


static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct sk_buff *opt_skb = NULL;

	/* Imagine: socket is IPv6. IPv4 packet arrives,
           goes to IPv4 receive handler and backlogged.
           From backlog it always goes here. Kerboom...
           Fortunately, dccp_rcv_established and rcv_established
           handle them correctly, but it is not case with
           dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
         */

	if (skb->protocol == htons(ETH_P_IP))
		return dccp_v4_do_rcv(sk, skb);

	if (sk_filter(sk, skb))
		goto discard;

	/*
         * socket locking is here for SMP purposes as backlog rcv is currently
         * called with bh processing disabled.
         */

	/* Do Stevens' IPV6_PKTOPTIONS.

           Yes, guys, it is the only place in our code, where we
           may make it not affecting IPv4.
           The rest of code is protocol independent,
           and I do not like idea to uglify IPv4.

           Actually, all the idea behind IPV6_PKTOPTIONS
           looks not very well thought. For now we latch
           options, received in the last packet, enqueued
           by tcp. Feel free to propose better solution.
                                               --ANK (980728)
         */
	if (np->rxopt.all)
	/*
         * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below
         *        (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example.
         */
		opt_skb = skb_clone(skb, GFP_ATOMIC);

	if (sk->sk_state == DCCP_OPEN) { /* Fast path */
		if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
			goto reset;
		if (opt_skb) {
			/* XXX This is where we would goto ipv6_pktoptions. */
			__kfree_skb(opt_skb);
		}
		return 0;
	}

	/*
         *  Step 3: Process LISTEN state
         *     If S.state == LISTEN,
         *       If P.type == Request or P contains a valid Init Cookie option,
         *            (* Must scan the packet's options to check for Init
         *               Cookies.  Only Init Cookies are processed here,
         *               however; other options are processed in Step 8.  This
         *               scan need only be performed if the endpoint uses Init
         *               Cookies *)
         *            (* Generate a new socket and switch to that socket *)
         *            Set S := new socket for this port pair
         *            S.state = RESPOND
         *            Choose S.ISS (initial seqno) or set from Init Cookies
         *            Initialize S.GAR := S.ISS
         *            Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
         *            Continue with S.state == RESPOND
         *            (* A Response packet will be generated in Step 11 *)
         *       Otherwise,
         *            Generate Reset(No Connection) unless P.type == Reset
         *            Drop packet and return
         *
         * NOTE: the check for the packet types is done in
         *       dccp_rcv_state_process
         */

	if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
		goto reset;
	if (opt_skb) {
		/* XXX This is where we would goto ipv6_pktoptions. */
		__kfree_skb(opt_skb);
	}
	return 0;

reset:
	dccp_v6_ctl_send_reset(sk, skb);
discard:
	if (opt_skb != NULL)
		__kfree_skb(opt_skb);
	kfree_skb(skb);
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Gerrit Renker
155
77.89%
2
40.00%
Arnaldo Carvalho de Melo
41
20.60%
1
20.00%
Hideaki Yoshifuji / 吉藤英明
3
1.51%
2
40.00%
Total
199
100.00%
5
100.00%



static int dccp_v6_rcv(struct sk_buff *skb)
{
	const struct dccp_hdr *dh;
	bool refcounted;
	struct sock *sk;
	int min_cov;

	/* Step 1: Check header basics */

	if (dccp_invalid_packet(skb))
		goto discard_it;

	/* Step 1: If header checksum is incorrect, drop packet and return. */
	if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
				     &ipv6_hdr(skb)->daddr)) {
		DCCP_WARN("dropped packet with invalid checksum\n");
		goto discard_it;
	}

	dh = dccp_hdr(skb);

	DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
	DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;

	if (dccp_packet_without_ack(skb))
		DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
	else
		DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);

lookup:
	sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh),
			        dh->dccph_sport, dh->dccph_dport,
				inet6_iif(skb), &refcounted);
	if (!sk) {
		dccp_pr_debug("failed to look up flow ID in table and "
			      "get corresponding socket\n");
		goto no_dccp_socket;
	}

	/*
         * Step 2:
         *      ... or S.state == TIMEWAIT,
         *              Generate Reset(No Connection) unless P.type == Reset
         *              Drop packet and return
         */
	if (sk->sk_state == DCCP_TIME_WAIT) {
		dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
		inet_twsk_put(inet_twsk(sk));
		goto no_dccp_socket;
	}

	if (sk->sk_state == DCCP_NEW_SYN_RECV)</