diff options
Diffstat (limited to 'net/ipv6/tcp_ipv6.c')
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 1965 |
1 files changed, 1965 insertions, 0 deletions
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c new file mode 100644 index 000000000..5193d0953 --- /dev/null +++ b/net/ipv6/tcp_ipv6.c @@ -0,0 +1,1965 @@ +/* + * TCP over IPv6 + * Linux INET6 implementation + * + * Authors: + * Pedro Roque <roque@di.fc.ul.pt> + * + * 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/bottom_half.h> +#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/slab.h> +#include <linux/uaccess.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/snmp.h> +#include <net/dsfield.h> +#include <net/timewait_sock.h> +#include <net/inet_common.h> +#include <net/secure_seq.h> +#include <net/tcp_memcontrol.h> +#include <net/busy_poll.h> +#include <net/secure_seq.h> + +#include <linux/proc_fs.h> +#include <linux/seq_file.h> + +#include <linux/crypto.h> +#include <linux/scatterlist.h> + +static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb); +static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, + struct request_sock *req); + +static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb); + +static const struct inet_connection_sock_af_ops ipv6_mapped; +static const struct inet_connection_sock_af_ops ipv6_specific; +#ifdef CONFIG_TCP_MD5SIG +static const struct tcp_sock_af_ops tcp_sock_ipv6_specific; +static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific; +#else +static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk, + const struct in6_addr *addr) +{ + return NULL; +} +#endif + +static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) +{ + struct dst_entry *dst = skb_dst(skb); + + if (dst) { + const struct rt6_info *rt = (const struct rt6_info *)dst; + + dst_hold(dst); + sk->sk_rx_dst = dst; + inet_sk(sk)->rx_dst_ifindex = skb->skb_iif; + if (rt->rt6i_node) + inet6_sk(sk)->rx_dst_cookie = rt->rt6i_node->fn_sernum; + } +} + +static __u32 tcp_v6_init_sequence(const struct sk_buff *skb) +{ + return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32, + ipv6_hdr(skb)->saddr.s6_addr32, + tcp_hdr(skb)->dest, + tcp_hdr(skb)->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, final; + struct rt6_info *rt; + struct flowi6 fl6; + 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(&fl6, 0, sizeof(fl6)); + + if (np->sndflow) { + fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK; + IP6_ECN_flow_init(fl6.flowlabel); + if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) { + struct ip6_flowlabel *flowlabel; + flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); + if (!flowlabel) + return -EINVAL; + 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(&sk->sk_v6_daddr, &usin->sin6_addr)) { + tp->rx_opt.ts_recent = 0; + tp->rx_opt.ts_recent_stamp = 0; + tp->write_seq = 0; + } + + sk->sk_v6_daddr = usin->sin6_addr; + np->flow_label = 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; +#ifdef CONFIG_TCP_MD5SIG + tp->af_specific = &tcp_sock_ipv6_mapped_specific; +#endif + + 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; +#ifdef CONFIG_TCP_MD5SIG + tp->af_specific = &tcp_sock_ipv6_specific; +#endif + goto failure; + } + np->saddr = sk->sk_v6_rcv_saddr; + + return err; + } + + if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) + saddr = &sk->sk_v6_rcv_saddr; + + fl6.flowi6_proto = IPPROTO_TCP; + fl6.daddr = sk->sk_v6_daddr; + fl6.saddr = saddr ? *saddr : np->saddr; + fl6.flowi6_oif = sk->sk_bound_dev_if; + fl6.flowi6_mark = sk->sk_mark; + fl6.fl6_dport = usin->sin6_port; + fl6.fl6_sport = inet->inet_sport; + + final_p = fl6_update_dst(&fl6, np->opt, &final); + + security_sk_classify_flow(sk, flowi6_to_flowi(&fl6)); + + dst = ip6_dst_lookup_flow(sk, &fl6, final_p); + if (IS_ERR(dst)) { + err = PTR_ERR(dst); + goto failure; + } + + if (!saddr) { + saddr = &fl6.saddr; + sk->sk_v6_rcv_saddr = *saddr; + } + + /* set the source address */ + np->saddr = *saddr; + inet->inet_rcv_saddr = LOOPBACK4_IPV6; + + sk->sk_gso_type = SKB_GSO_TCPV6; + __ip6_dst_store(sk, dst, NULL, NULL); + + rt = (struct rt6_info *) dst; + if (tcp_death_row.sysctl_tw_recycle && + !tp->rx_opt.ts_recent_stamp && + ipv6_addr_equal(&rt->rt6i_dst.addr, &sk->sk_v6_daddr)) + tcp_fetch_timewait_stamp(sk, dst); + + 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->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; + + ip6_set_txhash(sk); + +#ifdef CONFIG_TCP_STEALTH + /* If CONFIG_TCP_STEALTH is defined, we need to know the timestamp as + * early as possible and thus move taking the snapshot of tcp_time_stamp + * here. + */ + skb_mstamp_get(&tp->stealth.mstamp); + + if (!tp->write_seq && likely(!tp->repair) && + unlikely(tp->stealth.mode & TCP_STEALTH_MODE_AUTH)) + tp->write_seq = tcp_stealth_sequence_number(sk, + sk->sk_v6_daddr.s6_addr32, + sizeof(sk->sk_v6_daddr), + inet->inet_dport); +#endif + + if (!tp->write_seq && likely(!tp->repair)) + tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32, + sk->sk_v6_daddr.s6_addr32, + inet->inet_sport, + inet->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->inet_dport = 0; + sk->sk_route_caps = 0; + return err; +} + +static void tcp_v6_mtu_reduced(struct sock *sk) +{ + struct dst_entry *dst; + + if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) + return; + + dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info); + if (!dst) + return; + + if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) { + tcp_sync_mss(sk, dst_mtu(dst)); + tcp_simple_retransmit(sk); + } +} + +static void tcp_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 tcphdr *th = (struct tcphdr *)(skb->data+offset); + struct net *net = dev_net(skb->dev); + struct request_sock *fastopen; + struct ipv6_pinfo *np; + struct tcp_sock *tp; + __u32 seq, snd_una; + struct sock *sk; + int err; + + sk = __inet6_lookup_established(net, &tcp_hashinfo, + &hdr->daddr, th->dest, + &hdr->saddr, ntohs(th->source), + skb->dev->ifindex); + + if (!sk) { + ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev), + ICMP6_MIB_INERRORS); + return; + } + + if (sk->sk_state == TCP_TIME_WAIT) { + inet_twsk_put(inet_twsk(sk)); + return; + } + seq = ntohl(th->seq); + if (sk->sk_state == TCP_NEW_SYN_RECV) + return tcp_req_err(sk, seq); + + bh_lock_sock(sk); + if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG) + NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); + + if (sk->sk_state == TCP_CLOSE) + goto out; + + if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) { + NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP); + goto out; + } + + tp = tcp_sk(sk); + /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */ + fastopen = tp->fastopen_rsk; + snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una; + if (sk->sk_state != TCP_LISTEN && + !between(seq, snd_una, tp->snd_nxt)) { + NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS); + goto out; + } + + np = inet6_sk(sk); + + if (type == NDISC_REDIRECT) { + 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) { + /* We are not interested in TCP_LISTEN and open_requests + * (SYN-ACKs send out by Linux are always <576bytes so + * they should go through unfragmented). + */ + if (sk->sk_state == TCP_LISTEN) + goto out; + + if (!ip6_sk_accept_pmtu(sk)) + goto out; + + tp->mtu_info = ntohl(info); + if (!sock_owned_by_user(sk)) + tcp_v6_mtu_reduced(sk); + else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, + &tp->tsq_flags)) + sock_hold(sk); + goto out; + } + + icmpv6_err_convert(type, code, &err); + + /* Might be for an request_sock */ + switch (sk->sk_state) { + case TCP_SYN_SENT: + case TCP_SYN_RECV: + /* Only in fast or simultaneous open. If a fast open socket is + * is already accepted it is treated as a connected one below. + */ + if (fastopen && !fastopen->sk) + break; + + 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 dst_entry *dst, + struct flowi *fl, + struct request_sock *req, + u16 queue_mapping, + struct tcp_fastopen_cookie *foc) +{ + struct inet_request_sock *ireq = inet_rsk(req); + struct ipv6_pinfo *np = inet6_sk(sk); + struct flowi6 *fl6 = &fl->u.ip6; + struct sk_buff *skb; + int err = -ENOMEM; + + /* First, grab a route. */ + if (!dst && (dst = inet6_csk_route_req(sk, fl6, req)) == NULL) + goto done; + + skb = tcp_make_synack(sk, dst, req, foc); + + if (skb) { + __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr, + &ireq->ir_v6_rmt_addr); + + fl6->daddr = ireq->ir_v6_rmt_addr; + if (np->repflow && ireq->pktopts) + fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts)); + + skb_set_queue_mapping(skb, queue_mapping); + err = ip6_xmit(sk, skb, fl6, np->opt, np->tclass); + err = net_xmit_eval(err); + } + +done: + return err; +} + + +static void tcp_v6_reqsk_destructor(struct request_sock *req) +{ + kfree_skb(inet_rsk(req)->pktopts); +} + +#ifdef CONFIG_TCP_MD5SIG +static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk, + const struct in6_addr *addr) +{ + return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6); +} + +static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk, + const struct sock *addr_sk) +{ + return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr); +} + +static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval, + int optlen) +{ + struct tcp_md5sig cmd; + struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr; + + if (optlen < sizeof(cmd)) + return -EINVAL; + + if (copy_from_user(&cmd, optval, sizeof(cmd))) + return -EFAULT; + + if (sin6->sin6_family != AF_INET6) + return -EINVAL; + + if (!cmd.tcpm_keylen) { + if (ipv6_addr_v4mapped(&sin6->sin6_addr)) + return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3], + AF_INET); + return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr, + AF_INET6); + } + + if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) + return -EINVAL; + + if (ipv6_addr_v4mapped(&sin6->sin6_addr)) + return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3], + AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL); + + return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr, + AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL); +} + +static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp, + const struct in6_addr *daddr, + const struct in6_addr *saddr, int nbytes) +{ + struct tcp6_pseudohdr *bp; + struct scatterlist sg; + + bp = &hp->md5_blk.ip6; + /* 1. TCP pseudo-header (RFC2460) */ + bp->saddr = *saddr; + bp->daddr = *daddr; + bp->protocol = cpu_to_be32(IPPROTO_TCP); + bp->len = cpu_to_be32(nbytes); + + sg_init_one(&sg, bp, sizeof(*bp)); + return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp)); +} + +static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key, + const struct in6_addr *daddr, struct in6_addr *saddr, + const struct tcphdr *th) +{ + struct tcp_md5sig_pool *hp; + struct hash_desc *desc; + + hp = tcp_get_md5sig_pool(); + if (!hp) + goto clear_hash_noput; + desc = &hp->md5_desc; + + if (crypto_hash_init(desc)) + goto clear_hash; + if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2)) + goto clear_hash; + if (tcp_md5_hash_header(hp, th)) + goto clear_hash; + if (tcp_md5_hash_key(hp, key)) + goto clear_hash; + if (crypto_hash_final(desc, md5_hash)) + goto clear_hash; + + tcp_put_md5sig_pool(); + return 0; + +clear_hash: + tcp_put_md5sig_pool(); +clear_hash_noput: + memset(md5_hash, 0, 16); + return 1; +} + +static int tcp_v6_md5_hash_skb(char *md5_hash, + const struct tcp_md5sig_key *key, + const struct sock *sk, + const struct sk_buff *skb) +{ + const struct in6_addr *saddr, *daddr; + struct tcp_md5sig_pool *hp; + struct hash_desc *desc; + const struct tcphdr *th = tcp_hdr(skb); + + if (sk) { /* valid for establish/request sockets */ + saddr = &sk->sk_v6_rcv_saddr; + daddr = &sk->sk_v6_daddr; + } else { + const struct ipv6hdr *ip6h = ipv6_hdr(skb); + saddr = &ip6h->saddr; + daddr = &ip6h->daddr; + } + + hp = tcp_get_md5sig_pool(); + if (!hp) + goto clear_hash_noput; + desc = &hp->md5_desc; + + if (crypto_hash_init(desc)) + goto clear_hash; + + if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len)) + goto clear_hash; + if (tcp_md5_hash_header(hp, th)) + goto clear_hash; + if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) + goto clear_hash; + if (tcp_md5_hash_key(hp, key)) + goto clear_hash; + if (crypto_hash_final(desc, md5_hash)) + goto clear_hash; + + tcp_put_md5sig_pool(); + return 0; + +clear_hash: + tcp_put_md5sig_pool(); +clear_hash_noput: + memset(md5_hash, 0, 16); + return 1; +} + +static bool tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb) +{ + const __u8 *hash_location = NULL; + struct tcp_md5sig_key *hash_expected; + const struct ipv6hdr *ip6h = ipv6_hdr(skb); + const struct tcphdr *th = tcp_hdr(skb); + int genhash; + u8 newhash[16]; + + hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr); + hash_location = tcp_parse_md5sig_option(th); + + /* We've parsed the options - do we have a hash? */ + if (!hash_expected && !hash_location) + return false; + + if (hash_expected && !hash_location) { + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); + return true; + } + + if (!hash_expected && hash_location) { + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED); + return true; + } + + /* check the signature */ + genhash = tcp_v6_md5_hash_skb(newhash, + hash_expected, + NULL, skb); + + if (genhash || memcmp(hash_location, newhash, 16) != 0) { + net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n", + genhash ? "failed" : "mismatch", + &ip6h->saddr, ntohs(th->source), + &ip6h->daddr, ntohs(th->dest)); + return true; + } + return false; +} +#endif + +static void tcp_v6_init_req(struct request_sock *req, struct sock *sk, + struct sk_buff *skb) +{ + struct inet_request_sock *ireq = inet_rsk(req); + struct ipv6_pinfo *np = inet6_sk(sk); + + ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr; + ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr; + + /* 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 = tcp_v6_iif(skb); + + if (!TCP_SKB_CB(skb)->tcp_tw_isn && + (ipv6_opt_accepted(sk, skb, &TCP_SKB_CB(skb)->header.h6) || + np->rxopt.bits.rxinfo || + np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim || + np->rxopt.bits.rxohlim || np->repflow)) { + atomic_inc(&skb->users); + ireq->pktopts = skb; + } +} + +static struct dst_entry *tcp_v6_route_req(struct sock *sk, struct flowi *fl, + const struct request_sock *req, + bool *strict) +{ + if (strict) + *strict = true; + return inet6_csk_route_req(sk, &fl->u.ip6, req); +} + +struct request_sock_ops tcp6_request_sock_ops __read_mostly = { + .family = AF_INET6, + .obj_size = sizeof(struct tcp6_request_sock), + .rtx_syn_ack = tcp_rtx_synack, + .send_ack = tcp_v6_reqsk_send_ack, + .destructor = tcp_v6_reqsk_destructor, + .send_reset = tcp_v6_send_reset, + .syn_ack_timeout = tcp_syn_ack_timeout, +}; + +static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = { + .mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - + sizeof(struct ipv6hdr), +#ifdef CONFIG_TCP_MD5SIG + .req_md5_lookup = tcp_v6_md5_lookup, + .calc_md5_hash = tcp_v6_md5_hash_skb, +#endif + .init_req = tcp_v6_init_req, +#ifdef CONFIG_SYN_COOKIES + .cookie_init_seq = cookie_v6_init_sequence, +#endif + .route_req = tcp_v6_route_req, + .init_seq = tcp_v6_init_sequence, + .send_synack = tcp_v6_send_synack, + .queue_hash_add = inet6_csk_reqsk_queue_hash_add, +}; + +static void tcp_v6_send_response(struct sock *sk, struct sk_buff *skb, u32 seq, + u32 ack, u32 win, u32 tsval, u32 tsecr, + int oif, struct tcp_md5sig_key *key, int rst, + u8 tclass, u32 label) +{ + const struct tcphdr *th = tcp_hdr(skb); + struct tcphdr *t1; + struct sk_buff *buff; + struct flowi6 fl6; + struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); + struct sock *ctl_sk = net->ipv6.tcp_sk; + unsigned int tot_len = sizeof(struct tcphdr); + struct dst_entry *dst; + __be32 *topt; + + if (tsecr) + tot_len += TCPOLEN_TSTAMP_ALIGNED; +#ifdef CONFIG_TCP_MD5SIG + if (key) + tot_len += TCPOLEN_MD5SIG_ALIGNED; +#endif + + buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len, + GFP_ATOMIC); + if (!buff) + return; + + skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len); + + t1 = (struct tcphdr *) skb_push(buff, tot_len); + skb_reset_transport_header(buff); + + /* 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 = !rst || !th->ack; + t1->rst = rst; + t1->window = htons(win); + + topt = (__be32 *)(t1 + 1); + + if (tsecr) { + *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | + (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); + *topt++ = htonl(tsval); + *topt++ = htonl(tsecr); + } + +#ifdef CONFIG_TCP_MD5SIG + if (key) { + *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | + (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG); + tcp_v6_md5_hash_hdr((__u8 *)topt, key, + &ipv6_hdr(skb)->saddr, + &ipv6_hdr(skb)->daddr, t1); + } +#endif + + memset(&fl6, 0, sizeof(fl6)); + fl6.daddr = ipv6_hdr(skb)->saddr; + fl6.saddr = ipv6_hdr(skb)->daddr; + fl6.flowlabel = label; + + buff->ip_summed = CHECKSUM_PARTIAL; + buff->csum = 0; + + __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr); + + fl6.flowi6_proto = IPPROTO_TCP; + if (rt6_need_strict(&fl6.daddr) && !oif) + fl6.flowi6_oif = tcp_v6_iif(skb); + else + fl6.flowi6_oif = oif; + fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark); + fl6.fl6_dport = t1->dest; + fl6.fl6_sport = t1->source; + security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); + + /* Pass a socket to ip6_dst_lookup either it is for RST + * Underlying function will use this to retrieve the network + * namespace + */ + dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL); + if (!IS_ERR(dst)) { + skb_dst_set(buff, dst); + ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass); + TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS); + if (rst) + TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS); + return; + } + + kfree_skb(buff); +} + +static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb) +{ + const struct tcphdr *th = tcp_hdr(skb); + u32 seq = 0, ack_seq = 0; + struct tcp_md5sig_key *key = NULL; +#ifdef CONFIG_TCP_MD5SIG + const __u8 *hash_location = NULL; + struct ipv6hdr *ipv6h = ipv6_hdr(skb); + unsigned char newhash[16]; + int genhash; + struct sock *sk1 = NULL; +#endif + int oif; + + if (th->rst) + return; + + /* If sk not NULL, it means we did a successful lookup and incoming + * route had to be correct. prequeue might have dropped our dst. + */ + if (!sk && !ipv6_unicast_destination(skb)) + return; + +#ifdef CONFIG_TCP_MD5SIG + hash_location = tcp_parse_md5sig_option(th); + if (!sk && hash_location) { + /* + * active side is lost. Try to find listening socket through + * source port, and then find md5 key through listening socket. + * we are not loose security here: + * Incoming packet is checked with md5 hash with finding key, + * no RST generated if md5 hash doesn't match. + */ + sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev), + &tcp_hashinfo, &ipv6h->saddr, + th->source, &ipv6h->daddr, + ntohs(th->source), tcp_v6_iif(skb)); + if (!sk1) + return; + + rcu_read_lock(); + key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr); + if (!key) + goto release_sk1; + + genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb); + if (genhash || memcmp(hash_location, newhash, 16) != 0) + goto release_sk1; + } else { + key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL; + } +#endif + + if (th->ack) + seq = ntohl(th->ack_seq); + else + ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len - + (th->doff << 2); + + oif = sk ? sk->sk_bound_dev_if : 0; + tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0); + +#ifdef CONFIG_TCP_MD5SIG +release_sk1: + if (sk1) { + rcu_read_unlock(); + sock_put(sk1); + } +#endif +} + +static void tcp_v6_send_ack(struct sock *sk, struct sk_buff *skb, u32 seq, + u32 ack, u32 win, u32 tsval, u32 tsecr, int oif, + struct tcp_md5sig_key *key, u8 tclass, + u32 label) +{ + tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0, + tclass, label); +} + +static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb) +{ + struct inet_timewait_sock *tw = inet_twsk(sk); + struct tcp_timewait_sock *tcptw = tcp_twsk(sk); + + tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, + tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, + tcp_time_stamp + tcptw->tw_ts_offset, + tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw), + tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel)); + + inet_twsk_put(tw); +} + +static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, + struct request_sock *req) +{ + /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV + * sk->sk_state == TCP_SYN_RECV -> for Fast Open. + */ + tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ? + tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt, + tcp_rsk(req)->rcv_nxt, req->rcv_wnd, + tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if, + tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), + 0, 0); +} + + +static struct sock *tcp_v6_hnd_req(struct sock *sk, struct sk_buff *skb) +{ + const struct tcphdr *th = tcp_hdr(skb); + struct request_sock *req; + struct sock *nsk; + + /* Find possible connection requests. */ + req = inet6_csk_search_req(sk, th->source, + &ipv6_hdr(skb)->saddr, + &ipv6_hdr(skb)->daddr, tcp_v6_iif(skb)); + if (req) { + nsk = tcp_check_req(sk, skb, req, false); + if (!nsk) + reqsk_put(req); + return nsk; + } + nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo, + &ipv6_hdr(skb)->saddr, th->source, + &ipv6_hdr(skb)->daddr, ntohs(th->dest), + tcp_v6_iif(skb)); + + if (nsk) { + if (nsk->sk_state != TCP_TIME_WAIT) { + bh_lock_sock(nsk); + return nsk; + } + inet_twsk_put(inet_twsk(nsk)); + return NULL; + } + +#ifdef CONFIG_SYN_COOKIES + if (!th->syn) + sk = cookie_v6_check(sk, skb); +#endif + return sk; +} + +static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) +{ + if (skb->protocol == htons(ETH_P_IP)) + return tcp_v4_conn_request(sk, skb); + + if (!ipv6_unicast_destination(skb)) + goto drop; + + return tcp_conn_request(&tcp6_request_sock_ops, + &tcp_request_sock_ipv6_ops, sk, skb); + +drop: + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); + 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 inet_request_sock *ireq; + struct ipv6_pinfo *newnp, *np = inet6_sk(sk); + struct tcp6_sock *newtcp6sk; + struct inet_sock *newinet; + struct tcp_sock *newtp; + struct sock *newsk; +#ifdef CONFIG_TCP_MD5SIG + struct tcp_md5sig_key *key; +#endif + struct flowi6 fl6; + + if (skb->protocol == htons(ETH_P_IP)) { + /* + * v6 mapped + */ + + newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst); + + if (!newsk) + 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)); + + newnp->saddr = newsk->sk_v6_rcv_saddr; + + inet_csk(newsk)->icsk_af_ops = &ipv6_mapped; + newsk->sk_backlog_rcv = tcp_v4_do_rcv; +#ifdef CONFIG_TCP_MD5SIG + newtp->af_specific = &tcp_sock_ipv6_mapped_specific; +#endif + + newnp->ipv6_ac_list = NULL; + newnp->ipv6_fl_list = NULL; + newnp->pktoptions = NULL; + newnp->opt = NULL; + newnp->mcast_oif = tcp_v6_iif(skb); + newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; + newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb)); + if (np->repflow) + newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb)); + + /* + * 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; + } + + ireq = inet_rsk(req); + + if (sk_acceptq_is_full(sk)) + goto out_overflow; + + if (!dst) { + dst = inet6_csk_route_req(sk, &fl6, req); + if (!dst) + goto out; + } + + newsk = tcp_create_openreq_child(sk, req, skb); + if (!newsk) + goto out_nonewsk; + + /* + * 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); + inet6_sk_rx_dst_set(newsk, skb); + + 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)); + + 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; + + ip6_set_txhash(newsk); + + /* Now IPv6 options... + + First: no IPv4 options. + */ + newinet->inet_opt = NULL; + newnp->ipv6_ac_list = NULL; + newnp->ipv6_fl_list = NULL; + + /* Clone RX bits */ + newnp->rxopt.all = np->rxopt.all; + + /* Clone pktoptions received with SYN */ + newnp->pktoptions = NULL; + if (ireq->pktopts) { + newnp->pktoptions = skb_clone(ireq->pktopts, + sk_gfp_atomic(sk, GFP_ATOMIC)); + consume_skb(ireq->pktopts); + ireq->pktopts = NULL; + if (newnp->pktoptions) + skb_set_owner_r(newnp->pktoptions, newsk); + } + newnp->opt = NULL; + newnp->mcast_oif = tcp_v6_iif(skb); + newnp->mcast_hops = ipv6_hdr(skb)->hop_limit; + newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb)); + if (np->repflow) + newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb)); + + /* 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 (np->opt) + newnp->opt = ipv6_dup_options(newsk, np->opt); + + inet_csk(newsk)->icsk_ext_hdr_len = 0; + if (newnp->opt) + inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen + + newnp->opt->opt_flen); + + tcp_ca_openreq_child(newsk, dst); + + tcp_sync_mss(newsk, dst_mtu(dst)); + newtp->advmss = dst_metric_advmss(dst); + if (tcp_sk(sk)->rx_opt.user_mss && + tcp_sk(sk)->rx_opt.user_mss < newtp->advmss) + newtp->advmss = tcp_sk(sk)->rx_opt.user_mss; + + tcp_initialize_rcv_mss(newsk); + + newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; + newinet->inet_rcv_saddr = LOOPBACK4_IPV6; + +#ifdef CONFIG_TCP_MD5SIG + /* Copy over the MD5 key from the original socket */ + key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr); + if (key) { + /* We're using one, so create a matching key + * on the newsk structure. If we fail to get + * memory, then we end up not copying the key + * across. Shucks. + */ + tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr, + AF_INET6, key->key, key->keylen, + sk_gfp_atomic(sk, GFP_ATOMIC)); + } +#endif + + if (__inet_inherit_port(sk, newsk) < 0) { + inet_csk_prepare_forced_close(newsk); + tcp_done(newsk); + goto out; + } + __inet_hash(newsk, NULL); + + return newsk; + +out_overflow: + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); +out_nonewsk: + dst_release(dst); +out: + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); + 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 tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) +{ + struct ipv6_pinfo *np = inet6_sk(sk); + struct tcp_sock *tp = tcp_sk(sk); + struct tcphdr *th = tcp_hdr(skb); + 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, tcp_rcv_established and rcv_established + handle them correctly, but it is not case with + tcp_v6_hnd_req and tcp_v6_send_reset(). --ANK + */ + + if (skb->protocol == htons(ETH_P_IP)) + return tcp_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) + opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC)); + + if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ + struct dst_entry *dst = sk->sk_rx_dst; + + sock_rps_save_rxhash(sk, skb); + sk_mark_napi_id(sk, skb); + if (dst) { + if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif || + dst->ops->check(dst, np->rx_dst_cookie) == NULL) { + dst_release(dst); + sk->sk_rx_dst = NULL; + } + } + + tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len); + if (opt_skb) + goto ipv6_pktoptions; + return 0; + } + + if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb)) + goto csum_err; + +#ifdef CONFIG_TCP_STEALTH + if (sk->sk_state == TCP_LISTEN && th->syn && !th->fin && + tp->stealth.mode & TCP_STEALTH_MODE_AUTH && + tcp_stealth_do_auth(sk, skb)) + goto reset; +#endif + + if (sk->sk_state == TCP_LISTEN) { + struct sock *nsk = tcp_v6_hnd_req(sk, skb); + if (!nsk) + 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) { + sock_rps_save_rxhash(nsk, skb); + sk_mark_napi_id(sk, skb); + if (tcp_child_process(sk, nsk, skb)) + goto reset; + if (opt_skb) + __kfree_skb(opt_skb); + return 0; + } + } else + sock_rps_save_rxhash(sk, skb); + + if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) + goto reset; + if (opt_skb) + goto ipv6_pktoptions; + return 0; + +reset: + tcp_v6_send_reset(sk, skb); +discard: + if (opt_skb) + __kfree_skb(opt_skb); + kfree_skb(skb); + return 0; +csum_err: + TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS); + TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS); + goto discard; + + +ipv6_pktoptions: + /* Do you ask, what is it? + + 1. skb was enqueued by tcp. + 2. skb is added to tail of read queue, rather than out of order. + 3. socket is not in passive state. + 4. Finally, it really contains options, which user wants to receive. + */ + tp = tcp_sk(sk); + if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt && + !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) { + if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo) + np->mcast_oif = tcp_v6_iif(opt_skb); + if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) + np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit; + if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass) + np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb)); + if (np->repflow) + np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb)); + if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) { + skb_set_owner_r(opt_skb, sk); + opt_skb = xchg(&np->pktoptions, opt_skb); + } else { + __kfree_skb(opt_skb); + opt_skb = xchg(&np->pktoptions, NULL); + } + } + + kfree_skb(opt_skb); + return 0; +} + +static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr, + const struct tcphdr *th) +{ + /* This is tricky: we move IP6CB at its correct location into + * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because + * _decode_session6() uses IP6CB(). + * barrier() makes sure compiler won't play aliasing games. + */ + memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb), + sizeof(struct inet6_skb_parm)); + barrier(); + + TCP_SKB_CB(skb)->seq = ntohl(th->seq); + TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + + skb->len - th->doff*4); + TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); + TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th); + TCP_SKB_CB(skb)->tcp_tw_isn = 0; + TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr); + TCP_SKB_CB(skb)->sacked = 0; +} + +static void tcp_v6_restore_cb(struct sk_buff *skb) +{ + /* We need to move header back to the beginning if xfrm6_policy_check() + * and tcp_v6_fill_cb() are going to be called again. + */ + memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6, + sizeof(struct inet6_skb_parm)); +} + +static int tcp_v6_rcv(struct sk_buff *skb) +{ + const struct tcphdr *th; + const struct ipv6hdr *hdr; + struct sock *sk; + int ret; + struct net *net = dev_net(skb->dev); + + if (skb->pkt_type != PACKET_HOST) + goto discard_it; + + /* + * Count it even if it's bad. + */ + TCP_INC_STATS_BH(net, TCP_MIB_INSEGS); + + if (!pskb_may_pull(skb, sizeof(struct tcphdr))) + goto discard_it; + + th = tcp_hdr(skb); + + if (th->doff < sizeof(struct tcphdr)/4) + goto bad_packet; + if (!pskb_may_pull(skb, th->doff*4)) + goto discard_it; + + if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo)) + goto csum_error; + + th = tcp_hdr(skb); + hdr = ipv6_hdr(skb); + + sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest, + inet6_iif(skb)); + if (!sk) + goto no_tcp_socket; + +process: + if (sk->sk_state == TCP_TIME_WAIT) + goto do_time_wait; + + if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) { + NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP); + goto discard_and_relse; + } + + if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) + goto discard_and_relse; + + tcp_v6_fill_cb(skb, hdr, th); + +#ifdef CONFIG_TCP_MD5SIG + if (tcp_v6_inbound_md5_hash(sk, skb)) + goto discard_and_relse; +#endif + + if (sk_filter(sk, skb)) + goto discard_and_relse; + + sk_incoming_cpu_update(sk); + skb->dev = NULL; + + bh_lock_sock_nested(sk); + ret = 0; + if (!sock_owned_by_user(sk)) { + if (!tcp_prequeue(sk, skb)) + ret = tcp_v6_do_rcv(sk, skb); + } else if (unlikely(sk_add_backlog(sk, skb, + sk->sk_rcvbuf + sk->sk_sndbuf))) { + bh_unlock_sock(sk); + NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP); + goto discard_and_relse; + } + bh_unlock_sock(sk); + + sock_put(sk); + return ret ? -1 : 0; + +no_tcp_socket: + if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) + goto discard_it; + + tcp_v6_fill_cb(skb, hdr, th); + + if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) { +csum_error: + TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS); +bad_packet: + TCP_INC_STATS_BH(net, TCP_MIB_INERRS); + } else { + tcp_v6_send_reset(NULL, skb); + } + +discard_it: + kfree_skb(skb); + return 0; + +discard_and_relse: + sock_put(sk); + goto discard_it; + +do_time_wait: + if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { + inet_twsk_put(inet_twsk(sk)); + goto discard_it; + } + + tcp_v6_fill_cb(skb, hdr, th); + + if (skb->len < (th->doff<<2)) { + inet_twsk_put(inet_twsk(sk)); + goto bad_packet; + } + if (tcp_checksum_complete(skb)) { + inet_twsk_put(inet_twsk(sk)); + goto csum_error; + } + + switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) { + case TCP_TW_SYN: + { + struct sock *sk2; + + sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo, + &ipv6_hdr(skb)->saddr, th->source, + &ipv6_hdr(skb)->daddr, + ntohs(th->dest), tcp_v6_iif(skb)); + if (sk2) { + struct inet_timewait_sock *tw = inet_twsk(sk); + inet_twsk_deschedule(tw); + inet_twsk_put(tw); + sk = sk2; + tcp_v6_restore_cb(skb); + goto process; + } + /* Fall through to ACK */ + } + case TCP_TW_ACK: + tcp_v6_timewait_ack(sk, skb); + break; + case TCP_TW_RST: + tcp_v6_restore_cb(skb); + goto no_tcp_socket; + case TCP_TW_SUCCESS: + ; + } + goto discard_it; +} + +static void tcp_v6_early_demux(struct sk_buff *skb) +{ + const struct ipv6hdr *hdr; + const struct tcphdr *th; + struct sock *sk; + + if (skb->pkt_type != PACKET_HOST) + return; + + if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr))) + return; + + hdr = ipv6_hdr(skb); + th = tcp_hdr(skb); + + if (th->doff < sizeof(struct tcphdr) / 4) + return; + + /* Note : We use inet6_iif() here, not tcp_v6_iif() */ + sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo, + &hdr->saddr, th->source, + &hdr->daddr, ntohs(th->dest), + inet6_iif(skb)); + if (sk) { + skb->sk = sk; + skb->destructor = sock_edemux; + if (sk_fullsock(sk)) { + struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst); + + if (dst) + dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie); + if (dst && + inet_sk(sk)->rx_dst_ifindex == skb->skb_iif) + skb_dst_set_noref(skb, dst); + } + } +} + +static struct timewait_sock_ops tcp6_timewait_sock_ops = { + .twsk_obj_size = sizeof(struct tcp6_timewait_sock), + .twsk_unique = tcp_twsk_unique, + .twsk_destructor = tcp_twsk_destructor, +}; + +static const struct inet_connection_sock_af_ops ipv6_specific = { + .queue_xmit = inet6_csk_xmit, + .send_check = tcp_v6_send_check, + .rebuild_header = inet6_sk_rebuild_header, + .sk_rx_dst_set = inet6_sk_rx_dst_set, + .conn_request = tcp_v6_conn_request, + .syn_recv_sock = tcp_v6_syn_recv_sock, + .net_header_len = sizeof(struct ipv6hdr), + .net_frag_header_len = sizeof(struct frag_hdr), + .setsockopt = ipv6_setsockopt, + .getsockopt = ipv6_getsockopt, + .addr2sockaddr = inet6_csk_addr2sockaddr, + .sockaddr_len = sizeof(struct sockaddr_in6), + .bind_conflict = inet6_csk_bind_conflict, +#ifdef CONFIG_COMPAT + .compat_setsockopt = compat_ipv6_setsockopt, + .compat_getsockopt = compat_ipv6_getsockopt, +#endif + .mtu_reduced = tcp_v6_mtu_reduced, +}; + +#ifdef CONFIG_TCP_MD5SIG +static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = { + .md5_lookup = tcp_v6_md5_lookup, + .calc_md5_hash = tcp_v6_md5_hash_skb, + .md5_parse = tcp_v6_parse_md5_keys, +}; +#endif + +/* + * TCP over IPv4 via INET6 API + */ +static const struct inet_connection_sock_af_ops ipv6_mapped = { + .queue_xmit = ip_queue_xmit, + .send_check = tcp_v4_send_check, + .rebuild_header = inet_sk_rebuild_header, + .sk_rx_dst_set = inet_sk_rx_dst_set, + .conn_request = tcp_v6_conn_request, + .syn_recv_sock = tcp_v6_syn_recv_sock, + .net_header_len = sizeof(struct iphdr), + .setsockopt = ipv6_setsockopt, + .getsockopt = ipv6_getsockopt, + .addr2sockaddr = inet6_csk_addr2sockaddr, + .sockaddr_len = sizeof(struct sockaddr_in6), + .bind_conflict = inet6_csk_bind_conflict, +#ifdef CONFIG_COMPAT + .compat_setsockopt = compat_ipv6_setsockopt, + .compat_getsockopt = compat_ipv6_getsockopt, +#endif + .mtu_reduced = tcp_v4_mtu_reduced, +}; + +#ifdef CONFIG_TCP_MD5SIG +static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = { + .md5_lookup = tcp_v4_md5_lookup, + .calc_md5_hash = tcp_v4_md5_hash_skb, + .md5_parse = tcp_v6_parse_md5_keys, +}; +#endif + +/* NOTE: A lot of things set to zero explicitly by call to + * sk_alloc() so need not be done here. + */ +static int tcp_v6_init_sock(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + + tcp_init_sock(sk); + + icsk->icsk_af_ops = &ipv6_specific; + +#ifdef CONFIG_TCP_MD5SIG + tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific; +#endif + + return 0; +} + +static void tcp_v6_destroy_sock(struct sock *sk) +{ + tcp_v4_destroy_sock(sk); + inet6_destroy_sock(sk); +} + +#ifdef CONFIG_PROC_FS +/* Proc filesystem TCPv6 sock list dumping. */ +static void get_openreq6(struct seq_file *seq, + struct request_sock *req, int i, kuid_t uid) +{ + long ttd = req->rsk_timer.expires - jiffies; + const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr; + const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr; + + if (ttd < 0) + ttd = 0; + + seq_printf(seq, + "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X " + "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n", + i, + src->s6_addr32[0], src->s6_addr32[1], + src->s6_addr32[2], src->s6_addr32[3], + inet_rsk(req)->ir_num, + dest->s6_addr32[0], dest->s6_addr32[1], + dest->s6_addr32[2], dest->s6_addr32[3], + ntohs(inet_rsk(req)->ir_rmt_port), + TCP_SYN_RECV, + 0, 0, /* could print option size, but that is af dependent. */ + 1, /* timers active (only the expire timer) */ + jiffies_to_clock_t(ttd), + req->num_timeout, + from_kuid_munged(seq_user_ns(seq), uid), + 0, /* non standard timer */ + 0, /* open_requests have no inode */ + 0, req); +} + +static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i) +{ + const struct in6_addr *dest, *src; + __u16 destp, srcp; + int timer_active; + unsigned long timer_expires; + const struct inet_sock *inet = inet_sk(sp); + const struct tcp_sock *tp = tcp_sk(sp); + const struct inet_connection_sock *icsk = inet_csk(sp); + struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq; + + dest = &sp->sk_v6_daddr; + src = &sp->sk_v6_rcv_saddr; + destp = ntohs(inet->inet_dport); + srcp = ntohs(inet->inet_sport); + + if (icsk->icsk_pending == ICSK_TIME_RETRANS) { + timer_active = 1; + timer_expires = icsk->icsk_timeout; + } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { + timer_active = 4; + timer_expires = icsk->icsk_timeout; + } else if (timer_pending(&sp->sk_timer)) { + timer_active = 2; + timer_expires = sp->sk_timer.expires; + } else { + timer_active = 0; + timer_expires = jiffies; + } + + seq_printf(seq, + "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X " + "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n", + i, + src->s6_addr32[0], src->s6_addr32[1], + src->s6_addr32[2], src->s6_addr32[3], srcp, + dest->s6_addr32[0], dest->s6_addr32[1], + dest->s6_addr32[2], dest->s6_addr32[3], destp, + sp->sk_state, + tp->write_seq-tp->snd_una, + (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq), + timer_active, + jiffies_delta_to_clock_t(timer_expires - jiffies), + icsk->icsk_retransmits, + from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)), + icsk->icsk_probes_out, + sock_i_ino(sp), + atomic_read(&sp->sk_refcnt), sp, + jiffies_to_clock_t(icsk->icsk_rto), + jiffies_to_clock_t(icsk->icsk_ack.ato), + (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong, + tp->snd_cwnd, + sp->sk_state == TCP_LISTEN ? + (fastopenq ? fastopenq->max_qlen : 0) : + (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh) + ); +} + +static void get_timewait6_sock(struct seq_file *seq, + struct inet_timewait_sock *tw, int i) +{ + long delta = tw->tw_timer.expires - jiffies; + const struct in6_addr *dest, *src; + __u16 destp, srcp; + + dest = &tw->tw_v6_daddr; + src = &tw->tw_v6_rcv_saddr; + destp = ntohs(tw->tw_dport); + srcp = ntohs(tw->tw_sport); + + seq_printf(seq, + "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X " + "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n", + i, + src->s6_addr32[0], src->s6_addr32[1], + src->s6_addr32[2], src->s6_addr32[3], srcp, + dest->s6_addr32[0], dest->s6_addr32[1], + dest->s6_addr32[2], dest->s6_addr32[3], destp, + tw->tw_substate, 0, 0, + 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, + atomic_read(&tw->tw_refcnt), tw); +} + +static int tcp6_seq_show(struct seq_file *seq, void *v) +{ + struct tcp_iter_state *st; + struct sock *sk = v; + + if (v == SEQ_START_TOKEN) { + seq_puts(seq, + " sl " + "local_address " + "remote_address " + "st tx_queue rx_queue tr tm->when retrnsmt" + " uid timeout inode\n"); + goto out; + } + st = seq->private; + + switch (st->state) { + case TCP_SEQ_STATE_LISTENING: + case TCP_SEQ_STATE_ESTABLISHED: + if (sk->sk_state == TCP_TIME_WAIT) + get_timewait6_sock(seq, v, st->num); + else + get_tcp6_sock(seq, v, st->num); + break; + case TCP_SEQ_STATE_OPENREQ: + get_openreq6(seq, v, st->num, st->uid); + break; + } +out: + return 0; +} + +static const struct file_operations tcp6_afinfo_seq_fops = { + .owner = THIS_MODULE, + .open = tcp_seq_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_net +}; + +static struct tcp_seq_afinfo tcp6_seq_afinfo = { + .name = "tcp6", + .family = AF_INET6, + .seq_fops = &tcp6_afinfo_seq_fops, + .seq_ops = { + .show = tcp6_seq_show, + }, +}; + +int __net_init tcp6_proc_init(struct net *net) +{ + return tcp_proc_register(net, &tcp6_seq_afinfo); +} + +void tcp6_proc_exit(struct net *net) +{ + tcp_proc_unregister(net, &tcp6_seq_afinfo); +} +#endif + +static void tcp_v6_clear_sk(struct sock *sk, int size) +{ + struct inet_sock *inet = inet_sk(sk); + + /* we do not want to clear pinet6 field, because of RCU lookups */ + sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6)); + + size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6); + memset(&inet->pinet6 + 1, 0, size); +} + +struct proto tcpv6_prot = { + .name = "TCPv6", + .owner = THIS_MODULE, + .close = tcp_close, + .connect = tcp_v6_connect, + .disconnect = tcp_disconnect, + .accept = inet_csk_accept, + .ioctl = tcp_ioctl, + .init = tcp_v6_init_sock, + .destroy = tcp_v6_destroy_sock, + .shutdown = tcp_shutdown, + .setsockopt = tcp_setsockopt, + .getsockopt = tcp_getsockopt, + .recvmsg = tcp_recvmsg, + .sendmsg = tcp_sendmsg, + .sendpage = tcp_sendpage, + .backlog_rcv = tcp_v6_do_rcv, + .release_cb = tcp_release_cb, + .hash = inet_hash, + .unhash = inet_unhash, + .get_port = inet_csk_get_port, + .enter_memory_pressure = tcp_enter_memory_pressure, + .stream_memory_free = tcp_stream_memory_free, + .sockets_allocated = &tcp_sockets_allocated, + .memory_allocated = &tcp_memory_allocated, + .memory_pressure = &tcp_memory_pressure, + .orphan_count = &tcp_orphan_count, + .sysctl_mem = sysctl_tcp_mem, + .sysctl_wmem = sysctl_tcp_wmem, + .sysctl_rmem = sysctl_tcp_rmem, + .max_header = MAX_TCP_HEADER, + .obj_size = sizeof(struct tcp6_sock), + .slab_flags = SLAB_DESTROY_BY_RCU, + .twsk_prot = &tcp6_timewait_sock_ops, + .rsk_prot = &tcp6_request_sock_ops, + .h.hashinfo = &tcp_hashinfo, + .no_autobind = true, +#ifdef CONFIG_COMPAT + .compat_setsockopt = compat_tcp_setsockopt, + .compat_getsockopt = compat_tcp_getsockopt, +#endif +#ifdef CONFIG_MEMCG_KMEM + .proto_cgroup = tcp_proto_cgroup, +#endif + .clear_sk = tcp_v6_clear_sk, +}; + +static const struct inet6_protocol tcpv6_protocol = { + .early_demux = tcp_v6_early_demux, + .handler = tcp_v6_rcv, + .err_handler = tcp_v6_err, + .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, +}; + +static struct inet_protosw tcpv6_protosw = { + .type = SOCK_STREAM, + .protocol = IPPROTO_TCP, + .prot = &tcpv6_prot, + .ops = &inet6_stream_ops, + .flags = INET_PROTOSW_PERMANENT | + INET_PROTOSW_ICSK, +}; + +static int __net_init tcpv6_net_init(struct net *net) +{ + return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6, + SOCK_RAW, IPPROTO_TCP, net); +} + +static void __net_exit tcpv6_net_exit(struct net *net) +{ + inet_ctl_sock_destroy(net->ipv6.tcp_sk); +} + +static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list) +{ + inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6); +} + +static struct pernet_operations tcpv6_net_ops = { + .init = tcpv6_net_init, + .exit = tcpv6_net_exit, + .exit_batch = tcpv6_net_exit_batch, +}; + +int __init tcpv6_init(void) +{ + int ret; + + ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP); + if (ret) + goto out; + + /* register inet6 protocol */ + ret = inet6_register_protosw(&tcpv6_protosw); + if (ret) + goto out_tcpv6_protocol; + + ret = register_pernet_subsys(&tcpv6_net_ops); + if (ret) + goto out_tcpv6_protosw; +out: + return ret; + +out_tcpv6_protosw: + inet6_unregister_protosw(&tcpv6_protosw); +out_tcpv6_protocol: + inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP); + goto out; +} + +void tcpv6_exit(void) +{ + unregister_pernet_subsys(&tcpv6_net_ops); + inet6_unregister_protosw(&tcpv6_protosw); + inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP); +} |