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tcp_ipv6.c
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tcp_ipv6.c
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/*
* TCP over IPv6
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <[email protected]>
*
* $Id: tcp_ipv6.c,v 1.144 2002/02/01 22:01:04 davem Exp $
*
* Based on:
* linux/net/ipv4/tcp.c
* linux/net/ipv4/tcp_input.c
* linux/net/ipv4/tcp_output.c
*
* Fixes:
* Hideaki YOSHIFUJI : sin6_scope_id support
* YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
* Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
* a single port at the same time.
* YOSHIFUJI Hideaki @USAGI: convert /proc/net/tcp6 to seq_file.
*
* 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/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/jiffies.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/init.h>
#include <linux/jhash.h>
#include <linux/ipsec.h>
#include <linux/times.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/random.h>
#include <net/tcp.h>
#include <net/ndisc.h>
#include <net/inet6_hashtables.h>
#include <net/inet6_connection_sock.h>
#include <net/ipv6.h>
#include <net/transp_v6.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>
#include <net/ip6_checksum.h>
#include <net/inet_ecn.h>
#include <net/protocol.h>
#include <net/xfrm.h>
#include <net/addrconf.h>
#include <net/snmp.h>
#include <net/dsfield.h>
#include <net/timewait_sock.h>
#include <asm/uaccess.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
/* Socket used for sending RSTs and ACKs */
static struct socket *tcp6_socket;
static void tcp_v6_send_reset(struct sk_buff *skb);
static void tcp_v6_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req);
static void tcp_v6_send_check(struct sock *sk, int len,
struct sk_buff *skb);
static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
static struct inet_connection_sock_af_ops ipv6_mapped;
static struct inet_connection_sock_af_ops ipv6_specific;
static int tcp_v6_get_port(struct sock *sk, unsigned short snum)
{
return inet_csk_get_port(&tcp_hashinfo, sk, snum,
inet6_csk_bind_conflict);
}
static void tcp_v6_hash(struct sock *sk)
{
if (sk->sk_state != TCP_CLOSE) {
if (inet_csk(sk)->icsk_af_ops == &ipv6_mapped) {
tcp_prot.hash(sk);
return;
}
local_bh_disable();
__inet6_hash(&tcp_hashinfo, sk);
local_bh_enable();
}
}
static __inline__ u16 tcp_v6_check(struct tcphdr *th, int len,
struct in6_addr *saddr,
struct in6_addr *daddr,
unsigned long base)
{
return csum_ipv6_magic(saddr, daddr, len, IPPROTO_TCP, base);
}
static __u32 tcp_v6_init_sequence(struct sock *sk, struct sk_buff *skb)
{
if (skb->protocol == htons(ETH_P_IPV6)) {
return secure_tcpv6_sequence_number(skb->nh.ipv6h->daddr.s6_addr32,
skb->nh.ipv6h->saddr.s6_addr32,
skb->h.th->dest,
skb->h.th->source);
} else {
return secure_tcp_sequence_number(skb->nh.iph->daddr,
skb->nh.iph->saddr,
skb->h.th->dest,
skb->h.th->source);
}
}
static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
int addr_len)
{
struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
struct inet_sock *inet = inet_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
struct ipv6_pinfo *np = inet6_sk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct in6_addr *saddr = NULL, *final_p = NULL, final;
struct flowi fl;
struct dst_entry *dst;
int addr_type;
int err;
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] = 0x1;
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;
}
if (tp->rx_opt.ts_recent_stamp &&
!ipv6_addr_equal(&np->daddr, &usin->sin6_addr)) {
tp->rx_opt.ts_recent = 0;
tp->rx_opt.ts_recent_stamp = 0;
tp->write_seq = 0;
}
ipv6_addr_copy(&np->daddr, &usin->sin6_addr);
np->flow_label = fl.fl6_flowlabel;
/*
* TCP 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 = &ipv6_mapped;
sk->sk_backlog_rcv = tcp_v4_do_rcv;
err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
if (err) {
icsk->icsk_ext_hdr_len = exthdrlen;
icsk->icsk_af_ops = &ipv6_specific;
sk->sk_backlog_rcv = tcp_v6_do_rcv;
goto failure;
} else {
ipv6_addr_set(&np->saddr, 0, 0, htonl(0x0000FFFF),
inet->saddr);
ipv6_addr_set(&np->rcv_saddr, 0, 0, htonl(0x0000FFFF),
inet->rcv_saddr);
}
return err;
}
if (!ipv6_addr_any(&np->rcv_saddr))
saddr = &np->rcv_saddr;
fl.proto = IPPROTO_TCP;
ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
ipv6_addr_copy(&fl.fl6_src,
(saddr ? saddr : &np->saddr));
fl.oif = sk->sk_bound_dev_if;
fl.fl_ip_dport = usin->sin6_port;
fl.fl_ip_sport = inet->sport;
if (np->opt && np->opt->srcrt) {
struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
ipv6_addr_copy(&final, &fl.fl6_dst);
ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
final_p = &final;
}
security_sk_classify_flow(sk, &fl);
err = ip6_dst_lookup(sk, &dst, &fl);
if (err)
goto failure;
if (final_p)
ipv6_addr_copy(&fl.fl6_dst, final_p);
if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
goto failure;
if (saddr == NULL) {
saddr = &fl.fl6_src;
ipv6_addr_copy(&np->rcv_saddr, saddr);
}
/* set the source address */
ipv6_addr_copy(&np->saddr, saddr);
inet->rcv_saddr = LOOPBACK4_IPV6;
sk->sk_gso_type = SKB_GSO_TCPV6;
__ip6_dst_store(sk, dst, NULL, NULL);
icsk->icsk_ext_hdr_len = 0;
if (np->opt)
icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
np->opt->opt_nflen);
tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
inet->dport = usin->sin6_port;
tcp_set_state(sk, TCP_SYN_SENT);
err = inet6_hash_connect(&tcp_death_row, sk);
if (err)
goto late_failure;
if (!tp->write_seq)
tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
np->daddr.s6_addr32,
inet->sport,
inet->dport);
err = tcp_connect(sk);
if (err)
goto late_failure;
return 0;
late_failure:
tcp_set_state(sk, TCP_CLOSE);
__sk_dst_reset(sk);
failure:
inet->dport = 0;
sk->sk_route_caps = 0;
return err;
}
static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
int type, int code, int offset, __u32 info)
{
struct ipv6hdr *hdr = (struct ipv6hdr*)skb->data;
const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
struct ipv6_pinfo *np;
struct sock *sk;
int err;
struct tcp_sock *tp;
__u32 seq;
sk = inet6_lookup(&tcp_hashinfo, &hdr->daddr, th->dest, &hdr->saddr,
th->source, skb->dev->ifindex);
if (sk == NULL) {
ICMP6_INC_STATS_BH(__in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
return;
}
if (sk->sk_state == TCP_TIME_WAIT) {
inet_twsk_put((struct inet_timewait_sock *)sk);
return;
}
bh_lock_sock(sk);
if (sock_owned_by_user(sk))
NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
if (sk->sk_state == TCP_CLOSE)
goto out;
tp = tcp_sk(sk);
seq = ntohl(th->seq);
if (sk->sk_state != TCP_LISTEN &&
!between(seq, tp->snd_una, tp->snd_nxt)) {
NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
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) & (TCPF_LISTEN | TCPF_CLOSE))
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_TCP;
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_skb_classify_flow(skb, &fl);
if ((err = ip6_dst_lookup(sk, &dst, &fl))) {
sk->sk_err_soft = -err;
goto out;
}
if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0) {
sk->sk_err_soft = -err;
goto out;
}
} else
dst_hold(dst);
if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
tcp_sync_mss(sk, dst_mtu(dst));
tcp_simple_retransmit(sk);
} /* else let the usual retransmit timer handle it */
dst_release(dst);
goto out;
}
icmpv6_err_convert(type, code, &err);
/* Might be for an request_sock */
switch (sk->sk_state) {
struct request_sock *req, **prev;
case TCP_LISTEN:
if (sock_owned_by_user(sk))
goto out;
req = inet6_csk_search_req(sk, &prev, th->dest, &hdr->daddr,
&hdr->saddr, inet6_iif(skb));
if (!req)
goto out;
/* ICMPs are not backlogged, hence we cannot get
* an established socket here.
*/
BUG_TRAP(req->sk == NULL);
if (seq != tcp_rsk(req)->snt_isn) {
NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
goto out;
}
inet_csk_reqsk_queue_drop(sk, req, prev);
goto out;
case TCP_SYN_SENT:
case TCP_SYN_RECV: /* Cannot happen.
It can, it SYNs are crossed. --ANK */
if (!sock_owned_by_user(sk)) {
sk->sk_err = err;
sk->sk_error_report(sk); /* Wake people up to see the error (see connect in sock.c) */
tcp_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 tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
struct dst_entry *dst)
{
struct inet6_request_sock *treq = 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_TCP;
ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
ipv6_addr_copy(&fl.fl6_src, &treq->loc_addr);
fl.fl6_flowlabel = 0;
fl.oif = treq->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 &&
treq->pktopts) {
struct sk_buff *pktopts = treq->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 && opt->srcrt) {
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);
if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
goto done;
}
skb = tcp_make_synack(sk, dst, req);
if (skb) {
struct tcphdr *th = skb->h.th;
th->check = tcp_v6_check(th, skb->len,
&treq->loc_addr, &treq->rmt_addr,
csum_partial((char *)th, skb->len, skb->csum));
ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
err = ip6_xmit(sk, skb, &fl, opt, 0);
if (err == NET_XMIT_CN)
err = 0;
}
done:
if (opt && opt != np->opt)
sock_kfree_s(sk, opt, opt->tot_len);
dst_release(dst);
return err;
}
static void tcp_v6_reqsk_destructor(struct request_sock *req)
{
if (inet6_rsk(req)->pktopts)
kfree_skb(inet6_rsk(req)->pktopts);
}
static struct request_sock_ops tcp6_request_sock_ops = {
.family = AF_INET6,
.obj_size = sizeof(struct tcp6_request_sock),
.rtx_syn_ack = tcp_v6_send_synack,
.send_ack = tcp_v6_reqsk_send_ack,
.destructor = tcp_v6_reqsk_destructor,
.send_reset = tcp_v6_send_reset
};
static struct timewait_sock_ops tcp6_timewait_sock_ops = {
.twsk_obj_size = sizeof(struct tcp6_timewait_sock),
.twsk_unique = tcp_twsk_unique,
};
static void tcp_v6_send_check(struct sock *sk, int len, struct sk_buff *skb)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct tcphdr *th = skb->h.th;
if (skb->ip_summed == CHECKSUM_PARTIAL) {
th->check = ~csum_ipv6_magic(&np->saddr, &np->daddr, len, IPPROTO_TCP, 0);
skb->csum = offsetof(struct tcphdr, check);
} else {
th->check = csum_ipv6_magic(&np->saddr, &np->daddr, len, IPPROTO_TCP,
csum_partial((char *)th, th->doff<<2,
skb->csum));
}
}
static int tcp_v6_gso_send_check(struct sk_buff *skb)
{
struct ipv6hdr *ipv6h;
struct tcphdr *th;
if (!pskb_may_pull(skb, sizeof(*th)))
return -EINVAL;
ipv6h = skb->nh.ipv6h;
th = skb->h.th;
th->check = 0;
th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
IPPROTO_TCP, 0);
skb->csum = offsetof(struct tcphdr, check);
skb->ip_summed = CHECKSUM_PARTIAL;
return 0;
}
static void tcp_v6_send_reset(struct sk_buff *skb)
{
struct tcphdr *th = skb->h.th, *t1;
struct sk_buff *buff;
struct flowi fl;
if (th->rst)
return;
if (!ipv6_unicast_destination(skb))
return;
/*
* We need to grab some memory, and put together an RST,
* and then put it into the queue to be sent.
*/
buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + sizeof(struct tcphdr),
GFP_ATOMIC);
if (buff == NULL)
return;
skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + sizeof(struct tcphdr));
t1 = (struct tcphdr *) skb_push(buff,sizeof(struct tcphdr));
/* Swap the send and the receive. */
memset(t1, 0, sizeof(*t1));
t1->dest = th->source;
t1->source = th->dest;
t1->doff = sizeof(*t1)/4;
t1->rst = 1;
if(th->ack) {
t1->seq = th->ack_seq;
} else {
t1->ack = 1;
t1->ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin
+ skb->len - (th->doff<<2));
}
buff->csum = csum_partial((char *)t1, sizeof(*t1), 0);
memset(&fl, 0, sizeof(fl));
ipv6_addr_copy(&fl.fl6_dst, &skb->nh.ipv6h->saddr);
ipv6_addr_copy(&fl.fl6_src, &skb->nh.ipv6h->daddr);
t1->check = csum_ipv6_magic(&fl.fl6_src, &fl.fl6_dst,
sizeof(*t1), IPPROTO_TCP,
buff->csum);
fl.proto = IPPROTO_TCP;
fl.oif = inet6_iif(skb);
fl.fl_ip_dport = t1->dest;
fl.fl_ip_sport = t1->source;
security_skb_classify_flow(skb, &fl);
/* sk = NULL, but it is safe for now. RST socket required. */
if (!ip6_dst_lookup(NULL, &buff->dst, &fl)) {
if (xfrm_lookup(&buff->dst, &fl, NULL, 0) >= 0) {
ip6_xmit(tcp6_socket->sk, buff, &fl, NULL, 0);
TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
return;
}
}
kfree_skb(buff);
}
static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts)
{
struct tcphdr *th = skb->h.th, *t1;
struct sk_buff *buff;
struct flowi fl;
int tot_len = sizeof(struct tcphdr);
if (ts)
tot_len += 3*4;
buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
GFP_ATOMIC);
if (buff == NULL)
return;
skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
t1 = (struct tcphdr *) skb_push(buff,tot_len);
/* Swap the send and the receive. */
memset(t1, 0, sizeof(*t1));
t1->dest = th->source;
t1->source = th->dest;
t1->doff = tot_len/4;
t1->seq = htonl(seq);
t1->ack_seq = htonl(ack);
t1->ack = 1;
t1->window = htons(win);
if (ts) {
u32 *ptr = (u32*)(t1 + 1);
*ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
(TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
*ptr++ = htonl(tcp_time_stamp);
*ptr = htonl(ts);
}
buff->csum = csum_partial((char *)t1, tot_len, 0);
memset(&fl, 0, sizeof(fl));
ipv6_addr_copy(&fl.fl6_dst, &skb->nh.ipv6h->saddr);
ipv6_addr_copy(&fl.fl6_src, &skb->nh.ipv6h->daddr);
t1->check = csum_ipv6_magic(&fl.fl6_src, &fl.fl6_dst,
tot_len, IPPROTO_TCP,
buff->csum);
fl.proto = IPPROTO_TCP;
fl.oif = inet6_iif(skb);
fl.fl_ip_dport = t1->dest;
fl.fl_ip_sport = t1->source;
security_skb_classify_flow(skb, &fl);
if (!ip6_dst_lookup(NULL, &buff->dst, &fl)) {
if (xfrm_lookup(&buff->dst, &fl, NULL, 0) >= 0) {
ip6_xmit(tcp6_socket->sk, buff, &fl, NULL, 0);
TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
return;
}
}
kfree_skb(buff);
}
static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
struct inet_timewait_sock *tw = inet_twsk(sk);
const struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
tcptw->tw_ts_recent);
inet_twsk_put(tw);
}
static void tcp_v6_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req)
{
tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent);
}
static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
{
struct request_sock *req, **prev;
const struct tcphdr *th = skb->h.th;
struct sock *nsk;
/* Find possible connection requests. */
req = inet6_csk_search_req(sk, &prev, th->source,
&skb->nh.ipv6h->saddr,
&skb->nh.ipv6h->daddr, inet6_iif(skb));
if (req)
return tcp_check_req(sk, skb, req, prev);
nsk = __inet6_lookup_established(&tcp_hashinfo, &skb->nh.ipv6h->saddr,
th->source, &skb->nh.ipv6h->daddr,
ntohs(th->dest), inet6_iif(skb));
if (nsk) {
if (nsk->sk_state != TCP_TIME_WAIT) {
bh_lock_sock(nsk);
return nsk;
}
inet_twsk_put((struct inet_timewait_sock *)nsk);
return NULL;
}
#if 0 /*def CONFIG_SYN_COOKIES*/
if (!th->rst && !th->syn && th->ack)
sk = cookie_v6_check(sk, skb, &(IPCB(skb)->opt));
#endif
return sk;
}
/* FIXME: this is substantially similar to the ipv4 code.
* Can some kind of merge be done? -- erics
*/
static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
{
struct inet6_request_sock *treq;
struct ipv6_pinfo *np = inet6_sk(sk);
struct tcp_options_received tmp_opt;
struct tcp_sock *tp = tcp_sk(sk);
struct request_sock *req = NULL;
__u32 isn = TCP_SKB_CB(skb)->when;
if (skb->protocol == htons(ETH_P_IP))
return tcp_v4_conn_request(sk, skb);
if (!ipv6_unicast_destination(skb))
goto drop;
/*
* There are no SYN attacks on IPv6, yet...
*/
if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
if (net_ratelimit())
printk(KERN_INFO "TCPv6: dropping request, synflood is possible\n");
goto drop;
}
if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
goto drop;
req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
if (req == NULL)
goto drop;
tcp_clear_options(&tmp_opt);
tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
tmp_opt.user_mss = tp->rx_opt.user_mss;
tcp_parse_options(skb, &tmp_opt, 0);
tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
tcp_openreq_init(req, &tmp_opt, skb);
treq = inet6_rsk(req);
ipv6_addr_copy(&treq->rmt_addr, &skb->nh.ipv6h->saddr);
ipv6_addr_copy(&treq->loc_addr, &skb->nh.ipv6h->daddr);
TCP_ECN_create_request(req, skb->h.th);
treq->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);
treq->pktopts = skb;
}
treq->iif = sk->sk_bound_dev_if;
/* So that link locals have meaning */
if (!sk->sk_bound_dev_if &&
ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
treq->iif = inet6_iif(skb);
if (isn == 0)
isn = tcp_v6_init_sequence(sk,skb);
tcp_rsk(req)->snt_isn = isn;
security_inet_conn_request(sk, skb, req);
if (tcp_v6_send_synack(sk, req, NULL))
goto drop;
inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
return 0;
drop:
if (req)
reqsk_free(req);
return 0; /* don't send reset */
}
static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
struct request_sock *req,
struct dst_entry *dst)
{
struct inet6_request_sock *treq = inet6_rsk(req);
struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
struct tcp6_sock *newtcp6sk;
struct inet_sock *newinet;
struct tcp_sock *newtp;
struct sock *newsk;
struct ipv6_txoptions *opt;
if (skb->protocol == htons(ETH_P_IP)) {
/*
* v6 mapped
*/
newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
if (newsk == NULL)
return NULL;
newtcp6sk = (struct tcp6_sock *)newsk;
inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
newinet = inet_sk(newsk);
newnp = inet6_sk(newsk);
newtp = tcp_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 = &ipv6_mapped;
newsk->sk_backlog_rcv = tcp_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, tcp_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.
*/
tcp_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 && treq->pktopts) {
struct inet6_skb_parm *rxopt = IP6CB(treq->pktopts);
if (rxopt->srcrt)
opt = ipv6_invert_rthdr(sk, (struct ipv6_rt_hdr *)(treq->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_TCP;
ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
if (opt && opt->srcrt) {
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, &treq->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_req_classify_flow(req, &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 = tcp_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, tcp_create_openreq_child now does this for us, see the
* comment in that function for the gory details. -acme
*/
newsk->sk_gso_type = SKB_GSO_TCPV6;
__ip6_dst_store(newsk, dst, NULL, NULL);
newtcp6sk = (struct tcp6_sock *)newsk;
inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
newtp = tcp_sk(newsk);
newinet = inet_sk(newsk);
newnp = inet6_sk(newsk);
memcpy(newnp, np, sizeof(struct ipv6_pinfo));
ipv6_addr_copy(&newnp->daddr, &treq->rmt_addr);
ipv6_addr_copy(&newnp->saddr, &treq->loc_addr);
ipv6_addr_copy(&newnp->rcv_saddr, &treq->loc_addr);
newsk->sk_bound_dev_if = treq->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 (treq->pktopts != NULL) {
newnp->pktoptions = skb_clone(treq->pktopts, GFP_ATOMIC);
kfree_skb(treq->pktopts);
treq->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.
*/