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ipv6.c
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ipv6.c
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/*
* DCCP over IPv6
* Linux INET6 implementation
*
* Based on net/dccp6/ipv6.c
*
* Arnaldo Carvalho de Melo <[email protected]>
*
* 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/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 "dccp.h"
#include "ipv6.h"
#include "feat.h"
/* Socket used for sending RSTs and ACKs */
static struct socket *dccp_v6_ctl_socket;
static struct inet_connection_sock_af_ops dccp_ipv6_mapped;
static struct inet_connection_sock_af_ops dccp_ipv6_af_ops;
static int dccp_v6_get_port(struct sock *sk, unsigned short snum)
{
return inet_csk_get_port(&dccp_hashinfo, sk, snum,
inet6_csk_bind_conflict);
}
static void dccp_v6_hash(struct sock *sk)
{
if (sk->sk_state != DCCP_CLOSED) {
if (inet_csk(sk)->icsk_af_ops == &dccp_ipv6_mapped) {
dccp_hash(sk);
return;
}
local_bh_disable();
__inet6_hash(&dccp_hashinfo, sk);
local_bh_enable();
}
}
/* add pseudo-header to DCCP checksum stored in skb->csum */
static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
struct in6_addr *saddr,
struct in6_addr *daddr)
{
return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum);
}
static inline void dccp_v6_send_check(struct sock *sk, int unused_value,
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, &np->daddr);
}
static inline __u32 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
__be16 sport, __be16 dport )
{
return secure_tcpv6_sequence_number(saddr, daddr, sport, dport);
}
static inline __u32 dccp_v6_init_sequence(struct sk_buff *skb)
{
return secure_dccpv6_sequence_number(skb->nh.ipv6h->daddr.s6_addr32,
skb->nh.ipv6h->saddr.s6_addr32,
dccp_hdr(skb)->dccph_dport,
dccp_hdr(skb)->dccph_sport );
}
static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
int type, int code, int offset, __be32 info)
{
struct ipv6hdr *hdr = (struct ipv6hdr *)skb->data;
const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
struct ipv6_pinfo *np;
struct sock *sk;
int err;
__u64 seq;
sk = inet6_lookup(&dccp_hashinfo, &hdr->daddr, dh->dccph_dport,
&hdr->saddr, dh->dccph_sport, inet6_iif(skb));
if (sk == NULL) {
ICMP6_INC_STATS_BH(__in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
return;
}
if (sk->sk_state == DCCP_TIME_WAIT) {
inet_twsk_put(inet_twsk(sk));
return;
}
bh_lock_sock(sk);
if (sock_owned_by_user(sk))
NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
if (sk->sk_state == DCCP_CLOSED)
goto out;
np = inet6_sk(sk);
if (type == ICMPV6_PKT_TOOBIG) {
struct dst_entry *dst = NULL;
if (sock_owned_by_user(sk))
goto out;
if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
goto out;
/* icmp should have updated the destination cache entry */
dst = __sk_dst_check(sk, np->dst_cookie);
if (dst == NULL) {
struct inet_sock *inet = inet_sk(sk);
struct flowi fl;
/* BUGGG_FUTURE: Again, it is not clear how
to handle rthdr case. Ignore this complexity
for now.
*/
memset(&fl, 0, sizeof(fl));
fl.proto = IPPROTO_DCCP;
ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
ipv6_addr_copy(&fl.fl6_src, &np->saddr);
fl.oif = sk->sk_bound_dev_if;
fl.fl_ip_dport = inet->dport;
fl.fl_ip_sport = inet->sport;
security_sk_classify_flow(sk, &fl);
err = ip6_dst_lookup(sk, &dst, &fl);
if (err) {
sk->sk_err_soft = -err;
goto out;
}
err = xfrm_lookup(&dst, &fl, sk, 0);
if (err < 0) {
sk->sk_err_soft = -err;
goto out;
}
} else
dst_hold(dst);
if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
dccp_sync_mss(sk, dst_mtu(dst));
} /* else let the usual retransmit timer handle it */
dst_release(dst);
goto out;
}
icmpv6_err_convert(type, code, &err);
seq = DCCP_SKB_CB(skb)->dccpd_seq;
/* Might be for an request_sock */
switch (sk->sk_state) {
struct request_sock *req, **prev;
case DCCP_LISTEN:
if (sock_owned_by_user(sk))
goto out;
req = inet6_csk_search_req(sk, &prev, dh->dccph_dport,
&hdr->daddr, &hdr->saddr,
inet6_iif(skb));
if (req == NULL)
goto out;
/*
* ICMPs are not backlogged, hence we cannot get an established
* socket here.
*/
BUG_TRAP(req->sk == NULL);
if (seq != dccp_rsk(req)->dreq_iss) {
NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
goto out;
}
inet_csk_reqsk_queue_drop(sk, req, prev);
goto out;
case DCCP_REQUESTING:
case DCCP_RESPOND: /* Cannot happen.
It can, it SYNs are crossed. --ANK */
if (!sock_owned_by_user(sk)) {
DCCP_INC_STATS_BH(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);
}
static int dccp_v6_send_response(struct sock *sk, struct request_sock *req,
struct dst_entry *dst)
{
struct inet6_request_sock *ireq6 = inet6_rsk(req);
struct ipv6_pinfo *np = inet6_sk(sk);
struct sk_buff *skb;
struct ipv6_txoptions *opt = NULL;
struct in6_addr *final_p = NULL, final;
struct flowi fl;
int err = -1;
memset(&fl, 0, sizeof(fl));
fl.proto = IPPROTO_DCCP;
ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
ipv6_addr_copy(&fl.fl6_src, &ireq6->loc_addr);
fl.fl6_flowlabel = 0;
fl.oif = ireq6->iif;
fl.fl_ip_dport = inet_rsk(req)->rmt_port;
fl.fl_ip_sport = inet_sk(sk)->sport;
security_req_classify_flow(req, &fl);
if (dst == NULL) {
opt = np->opt;
if (opt == NULL &&
np->rxopt.bits.osrcrt == 2 &&
ireq6->pktopts) {
struct sk_buff *pktopts = ireq6->pktopts;
struct inet6_skb_parm *rxopt = IP6CB(pktopts);
if (rxopt->srcrt)
opt = ipv6_invert_rthdr(sk,
(struct ipv6_rt_hdr *)(pktopts->nh.raw +
rxopt->srcrt));
}
if (opt != NULL && opt->srcrt != NULL) {
const struct rt0_hdr *rt0 = (struct rt0_hdr *)opt->srcrt;
ipv6_addr_copy(&final, &fl.fl6_dst);
ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
final_p = &final;
}
err = ip6_dst_lookup(sk, &dst, &fl);
if (err)
goto done;
if (final_p)
ipv6_addr_copy(&fl.fl6_dst, final_p);
err = xfrm_lookup(&dst, &fl, sk, 0);
if (err < 0)
goto done;
}
skb = dccp_make_response(sk, dst, req);
if (skb != NULL) {
struct dccp_hdr *dh = dccp_hdr(skb);
dh->dccph_checksum = dccp_v6_csum_finish(skb,
&ireq6->loc_addr,
&ireq6->rmt_addr);
ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
err = ip6_xmit(sk, skb, &fl, opt, 0);
err = net_xmit_eval(err);
}
done:
if (opt != NULL && opt != np->opt)
sock_kfree_s(sk, opt, opt->tot_len);
dst_release(dst);
return err;
}
static void dccp_v6_reqsk_destructor(struct request_sock *req)
{
if (inet6_rsk(req)->pktopts != NULL)
kfree_skb(inet6_rsk(req)->pktopts);
}
static void dccp_v6_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
{
struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_reset);
struct sk_buff *skb;
struct flowi fl;
u64 seqno = 0;
if (rxdh->dccph_type == DCCP_PKT_RESET)
return;
if (!ipv6_unicast_destination(rxskb))
return;
skb = alloc_skb(dccp_v6_ctl_socket->sk->sk_prot->max_header,
GFP_ATOMIC);
if (skb == NULL)
return;
skb_reserve(skb, dccp_v6_ctl_socket->sk->sk_prot->max_header);
dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
/* Swap the send and the receive. */
dh->dccph_type = DCCP_PKT_RESET;
dh->dccph_sport = rxdh->dccph_dport;
dh->dccph_dport = rxdh->dccph_sport;
dh->dccph_doff = dccp_hdr_reset_len / 4;
dh->dccph_x = 1;
dccp_hdr_reset(skb)->dccph_reset_code =
DCCP_SKB_CB(rxskb)->dccpd_reset_code;
/* See "8.3.1. Abnormal Termination" in RFC 4340 */
if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
dccp_hdr_set_seq(dh, seqno);
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), DCCP_SKB_CB(rxskb)->dccpd_seq);
dccp_csum_outgoing(skb);
dh->dccph_checksum = dccp_v6_csum_finish(skb, &rxskb->nh.ipv6h->saddr,
&rxskb->nh.ipv6h->daddr);
memset(&fl, 0, sizeof(fl));
ipv6_addr_copy(&fl.fl6_dst, &rxskb->nh.ipv6h->saddr);
ipv6_addr_copy(&fl.fl6_src, &rxskb->nh.ipv6h->daddr);
fl.proto = IPPROTO_DCCP;
fl.oif = inet6_iif(rxskb);
fl.fl_ip_dport = dh->dccph_dport;
fl.fl_ip_sport = dh->dccph_sport;
security_skb_classify_flow(rxskb, &fl);
/* sk = NULL, but it is safe for now. RST socket required. */
if (!ip6_dst_lookup(NULL, &skb->dst, &fl)) {
if (xfrm_lookup(&skb->dst, &fl, NULL, 0) >= 0) {
ip6_xmit(dccp_v6_ctl_socket->sk, skb, &fl, NULL, 0);
DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
return;
}
}
kfree_skb(skb);
}
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,
};
static struct sock *dccp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
{
const struct dccp_hdr *dh = dccp_hdr(skb);
const struct ipv6hdr *iph = skb->nh.ipv6h;
struct sock *nsk;
struct request_sock **prev;
/* Find possible connection requests. */
struct request_sock *req = inet6_csk_search_req(sk, &prev,
dh->dccph_sport,
&iph->saddr,
&iph->daddr,
inet6_iif(skb));
if (req != NULL)
return dccp_check_req(sk, skb, req, prev);
nsk = __inet6_lookup_established(&dccp_hashinfo,
&iph->saddr, dh->dccph_sport,
&iph->daddr, ntohs(dh->dccph_dport),
inet6_iif(skb));
if (nsk != NULL) {
if (nsk->sk_state != DCCP_TIME_WAIT) {
bh_lock_sock(nsk);
return nsk;
}
inet_twsk_put(inet_twsk(nsk));
return NULL;
}
return sk;
}
static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
{
struct request_sock *req;
struct dccp_request_sock *dreq;
struct inet6_request_sock *ireq6;
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);
__u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;
if (skb->protocol == htons(ETH_P_IP))
return dccp_v4_conn_request(sk, skb);
if (!ipv6_unicast_destination(skb))
goto drop;
if (dccp_bad_service_code(sk, service)) {
reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
goto drop;
}
/*
* There are no SYN attacks on IPv6, yet...
*/
if (inet_csk_reqsk_queue_is_full(sk))
goto drop;
if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
goto drop;
req = inet6_reqsk_alloc(&dccp6_request_sock_ops);
if (req == NULL)
goto drop;
if (dccp_parse_options(sk, skb))
goto drop_and_free;
dccp_reqsk_init(req, skb);
if (security_inet_conn_request(sk, skb, req))
goto drop_and_free;
ireq6 = inet6_rsk(req);
ipv6_addr_copy(&ireq6->rmt_addr, &skb->nh.ipv6h->saddr);
ipv6_addr_copy(&ireq6->loc_addr, &skb->nh.ipv6h->daddr);
ireq6->pktopts = NULL;
if (ipv6_opt_accepted(sk, skb) ||
np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
atomic_inc(&skb->users);
ireq6->pktopts = skb;
}
ireq6->iif = sk->sk_bound_dev_if;
/* So that link locals have meaning */
if (!sk->sk_bound_dev_if &&
ipv6_addr_type(&ireq6->rmt_addr) & IPV6_ADDR_LINKLOCAL)
ireq6->iif = inet6_iif(skb);
/*
* Step 3: Process LISTEN state
*
* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
*
* In fact we defer setting S.GSR, S.SWL, S.SWH to
* dccp_create_openreq_child.
*/
dreq = dccp_rsk(req);
dreq->dreq_isr = dcb->dccpd_seq;
dreq->dreq_iss = dccp_v6_init_sequence(skb);
dreq->dreq_service = service;
if (dccp_v6_send_response(sk, req, NULL))
goto drop_and_free;
inet6_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
return 0;
drop_and_free:
reqsk_free(req);
drop:
DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
dcb->dccpd_reset_code = reset_code;
return -1;
}
static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
struct sk_buff *skb,
struct request_sock *req,
struct dst_entry *dst)
{
struct inet6_request_sock *ireq6 = inet6_rsk(req);
struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
struct inet_sock *newinet;
struct dccp_sock *newdp;
struct dccp6_sock *newdp6;
struct sock *newsk;
struct ipv6_txoptions *opt;
if (skb->protocol == htons(ETH_P_IP)) {
/*
* v6 mapped
*/
newsk = dccp_v4_request_recv_sock(sk, skb, req, dst);
if (newsk == NULL)
return NULL;
newdp6 = (struct dccp6_sock *)newsk;
newdp = dccp_sk(newsk);
newinet = inet_sk(newsk);
newinet->pinet6 = &newdp6->inet6;
newnp = inet6_sk(newsk);
memcpy(newnp, np, sizeof(struct ipv6_pinfo));
ipv6_addr_set(&newnp->daddr, 0, 0, htonl(0x0000FFFF),
newinet->daddr);
ipv6_addr_set(&newnp->saddr, 0, 0, htonl(0x0000FFFF),
newinet->saddr);
ipv6_addr_copy(&newnp->rcv_saddr, &newnp->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 = skb->nh.ipv6h->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;
}
opt = np->opt;
if (sk_acceptq_is_full(sk))
goto out_overflow;
if (np->rxopt.bits.osrcrt == 2 && opt == NULL && ireq6->pktopts) {
const struct inet6_skb_parm *rxopt = IP6CB(ireq6->pktopts);
if (rxopt->srcrt)
opt = ipv6_invert_rthdr(sk,
(struct ipv6_rt_hdr *)(ireq6->pktopts->nh.raw +
rxopt->srcrt));
}
if (dst == NULL) {
struct in6_addr *final_p = NULL, final;
struct flowi fl;
memset(&fl, 0, sizeof(fl));
fl.proto = IPPROTO_DCCP;
ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
if (opt != NULL && opt->srcrt != NULL) {
const struct rt0_hdr *rt0 = (struct rt0_hdr *)opt->srcrt;
ipv6_addr_copy(&final, &fl.fl6_dst);
ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
final_p = &final;
}
ipv6_addr_copy(&fl.fl6_src, &ireq6->loc_addr);
fl.oif = sk->sk_bound_dev_if;
fl.fl_ip_dport = inet_rsk(req)->rmt_port;
fl.fl_ip_sport = inet_sk(sk)->sport;
security_sk_classify_flow(sk, &fl);
if (ip6_dst_lookup(sk, &dst, &fl))
goto out;
if (final_p)
ipv6_addr_copy(&fl.fl6_dst, final_p);
if ((xfrm_lookup(&dst, &fl, sk, 0)) < 0)
goto out;
}
newsk = dccp_create_openreq_child(sk, req, skb);
if (newsk == NULL)
goto out;
/*
* 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;
newdp = dccp_sk(newsk);
newnp = inet6_sk(newsk);
memcpy(newnp, np, sizeof(struct ipv6_pinfo));
ipv6_addr_copy(&newnp->daddr, &ireq6->rmt_addr);
ipv6_addr_copy(&newnp->saddr, &ireq6->loc_addr);
ipv6_addr_copy(&newnp->rcv_saddr, &ireq6->loc_addr);
newsk->sk_bound_dev_if = ireq6->iif;
/* Now IPv6 options...
First: no IPv4 options.
*/
newinet->opt = NULL;
/* Clone RX bits */
newnp->rxopt.all = np->rxopt.all;
/* Clone pktoptions received with SYN */
newnp->pktoptions = NULL;
if (ireq6->pktopts != NULL) {
newnp->pktoptions = skb_clone(ireq6->pktopts, GFP_ATOMIC);
kfree_skb(ireq6->pktopts);
ireq6->pktopts = NULL;
if (newnp->pktoptions)
skb_set_owner_r(newnp->pktoptions, newsk);
}
newnp->opt = NULL;
newnp->mcast_oif = inet6_iif(skb);
newnp->mcast_hops = skb->nh.ipv6h->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.
*/
if (opt != NULL) {
newnp->opt = ipv6_dup_options(newsk, opt);
if (opt != np->opt)
sock_kfree_s(sk, opt, opt->tot_len);
}
inet_csk(newsk)->icsk_ext_hdr_len = 0;
if (newnp->opt != NULL)
inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
newnp->opt->opt_flen);
dccp_sync_mss(newsk, dst_mtu(dst));
newinet->daddr = newinet->saddr = newinet->rcv_saddr = LOOPBACK4_IPV6;
__inet6_hash(&dccp_hashinfo, newsk);
inet_inherit_port(&dccp_hashinfo, sk, newsk);
return newsk;
out_overflow:
NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
out:
NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
if (opt != NULL && opt != np->opt)
sock_kfree_s(sk, opt, opt->tot_len);
dst_release(dst);
return NULL;
}
/* 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 (sk->sk_state == DCCP_LISTEN) {
struct sock *nsk = dccp_v6_hnd_req(sk, skb);
if (nsk == NULL)
goto discard;
/*
* Queue it on the new socket if the new socket is active,
* otherwise we just shortcircuit this and continue with
* the new socket..
*/
if (nsk != sk) {
if (dccp_child_process(sk, nsk, skb))
goto reset;
if (opt_skb != NULL)
__kfree_skb(opt_skb);
return 0;
}
}
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;
}
static int dccp_v6_rcv(struct sk_buff **pskb)
{
const struct dccp_hdr *dh;
struct sk_buff *skb = *pskb;
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, &skb->nh.ipv6h->saddr,
&skb->nh.ipv6h->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(skb);
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);
/* Step 2:
* Look up flow ID in table and get corresponding socket */
sk = __inet6_lookup(&dccp_hashinfo, &skb->nh.ipv6h->saddr,
dh->dccph_sport,
&skb->nh.ipv6h->daddr, ntohs(dh->dccph_dport),
inet6_iif(skb));
/*
* Step 2:
* If no socket ...
*/
if (sk == NULL) {
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;
}
/*
* RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
* o if MinCsCov = 0, only packets with CsCov = 0 are accepted
* o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
*/
min_cov = dccp_sk(sk)->dccps_pcrlen;
if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) {
dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
dh->dccph_cscov, min_cov);
/* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
goto discard_and_relse;
}
if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
goto discard_and_relse;
return sk_receive_skb(sk, skb, 1) ? -1 : 0;
no_dccp_socket:
if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
goto discard_it;
/*
* Step 2:
* If no socket ...
* Generate Reset(No Connection) unless P.type == Reset
* Drop packet and return
*/
if (dh->dccph_type != DCCP_PKT_RESET) {
DCCP_SKB_CB(skb)->dccpd_reset_code =
DCCP_RESET_CODE_NO_CONNECTION;
dccp_v6_ctl_send_reset(sk, skb);
}
discard_it:
kfree_skb(skb);
return 0;
discard_and_relse:
sock_put(sk);
goto discard_it;
}
static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
int addr_len)
{
struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
struct inet_connection_sock *icsk = inet_csk(sk);
struct inet_sock *inet = inet_sk(sk);
struct ipv6_pinfo *np = inet6_sk(sk);
struct dccp_sock *dp = dccp_sk(sk);
struct in6_addr *saddr = NULL, *final_p = NULL, final;
struct flowi fl;
struct dst_entry *dst;
int addr_type;
int err;
dp->dccps_role = DCCP_ROLE_CLIENT;
if (addr_len < SIN6_LEN_RFC2133)
return -EINVAL;
if (usin->sin6_family != AF_INET6)
return -EAFNOSUPPORT;
memset(&fl, 0, sizeof(fl));
if (np->sndflow) {
fl.fl6_flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
IP6_ECN_flow_init(fl.fl6_flowlabel);
if (fl.fl6_flowlabel & IPV6_FLOWLABEL_MASK) {
struct ip6_flowlabel *flowlabel;
flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
if (flowlabel == NULL)
return -EINVAL;
ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
fl6_sock_release(flowlabel);
}
}
/*
* connect() to INADDR_ANY means loopback (BSD'ism).
*/
if (ipv6_addr_any(&usin->sin6_addr))
usin->sin6_addr.s6_addr[15] = 1;
addr_type = ipv6_addr_type(&usin->sin6_addr);
if (addr_type & IPV6_ADDR_MULTICAST)
return -ENETUNREACH;
if (addr_type & IPV6_ADDR_LINKLOCAL) {
if (addr_len >= sizeof(struct sockaddr_in6) &&
usin->sin6_scope_id) {
/* If interface is set while binding, indices
* must coincide.
*/
if (sk->sk_bound_dev_if &&
sk->sk_bound_dev_if != usin->sin6_scope_id)
return -EINVAL;
sk->sk_bound_dev_if = usin->sin6_scope_id;
}
/* Connect to link-local address requires an interface */
if (!sk->sk_bound_dev_if)
return -EINVAL;
}
ipv6_addr_copy(&np->daddr, &usin->sin6_addr);
np->flow_label = fl.fl6_flowlabel;
/*
* DCCP over IPv4
*/
if (addr_type == IPV6_ADDR_MAPPED) {
u32 exthdrlen = icsk->icsk_ext_hdr_len;
struct sockaddr_in sin;
SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
if (__ipv6_only_sock(sk))
return -ENETUNREACH;
sin.sin_family = AF_INET;
sin.sin_port = usin->sin6_port;
sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
icsk->icsk_af_ops = &dccp_ipv6_mapped;
sk->sk_backlog_rcv = dccp_v4_do_rcv;