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![Arnaldo Carvalho de Melo](/assets/img/avatar_default.png)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1077 lines
28 KiB
C
1077 lines
28 KiB
C
/*
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* net/dccp/ipv4.c
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*
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* An implementation of the DCCP protocol
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* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/dccp.h>
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#include <linux/icmp.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/random.h>
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#include <net/icmp.h>
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#include <net/inet_common.h>
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#include <net/inet_hashtables.h>
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#include <net/inet_sock.h>
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#include <net/protocol.h>
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#include <net/sock.h>
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#include <net/timewait_sock.h>
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#include <net/tcp_states.h>
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#include <net/xfrm.h>
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#include "ackvec.h"
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#include "ccid.h"
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#include "dccp.h"
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#include "feat.h"
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/*
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* This is the global socket data structure used for responding to
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* the Out-of-the-blue (OOTB) packets. A control sock will be created
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* for this socket at the initialization time.
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*/
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static struct socket *dccp_v4_ctl_socket;
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static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
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{
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return inet_csk_get_port(&dccp_hashinfo, sk, snum,
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inet_csk_bind_conflict);
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}
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int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
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{
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struct inet_sock *inet = inet_sk(sk);
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struct dccp_sock *dp = dccp_sk(sk);
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const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
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struct rtable *rt;
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__be32 daddr, nexthop;
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int tmp;
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int err;
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dp->dccps_role = DCCP_ROLE_CLIENT;
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if (addr_len < sizeof(struct sockaddr_in))
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return -EINVAL;
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if (usin->sin_family != AF_INET)
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return -EAFNOSUPPORT;
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nexthop = daddr = usin->sin_addr.s_addr;
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if (inet->opt != NULL && inet->opt->srr) {
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if (daddr == 0)
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return -EINVAL;
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nexthop = inet->opt->faddr;
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}
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tmp = ip_route_connect(&rt, nexthop, inet->saddr,
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RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
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IPPROTO_DCCP,
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inet->sport, usin->sin_port, sk, 1);
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if (tmp < 0)
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return tmp;
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if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
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ip_rt_put(rt);
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return -ENETUNREACH;
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}
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if (inet->opt == NULL || !inet->opt->srr)
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daddr = rt->rt_dst;
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if (inet->saddr == 0)
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inet->saddr = rt->rt_src;
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inet->rcv_saddr = inet->saddr;
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inet->dport = usin->sin_port;
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inet->daddr = daddr;
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inet_csk(sk)->icsk_ext_hdr_len = 0;
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if (inet->opt != NULL)
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inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
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/*
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* Socket identity is still unknown (sport may be zero).
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* However we set state to DCCP_REQUESTING and not releasing socket
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* lock select source port, enter ourselves into the hash tables and
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* complete initialization after this.
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*/
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dccp_set_state(sk, DCCP_REQUESTING);
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err = inet_hash_connect(&dccp_death_row, sk);
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if (err != 0)
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goto failure;
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err = ip_route_newports(&rt, IPPROTO_DCCP, inet->sport, inet->dport,
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sk);
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if (err != 0)
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goto failure;
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/* OK, now commit destination to socket. */
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sk_setup_caps(sk, &rt->u.dst);
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dp->dccps_iss = secure_dccp_sequence_number(inet->saddr, inet->daddr,
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inet->sport, inet->dport);
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inet->id = dp->dccps_iss ^ jiffies;
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err = dccp_connect(sk);
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rt = NULL;
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if (err != 0)
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goto failure;
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out:
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return err;
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failure:
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/*
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* This unhashes the socket and releases the local port, if necessary.
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*/
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dccp_set_state(sk, DCCP_CLOSED);
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ip_rt_put(rt);
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sk->sk_route_caps = 0;
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inet->dport = 0;
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goto out;
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}
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EXPORT_SYMBOL_GPL(dccp_v4_connect);
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/*
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* This routine does path mtu discovery as defined in RFC1191.
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*/
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static inline void dccp_do_pmtu_discovery(struct sock *sk,
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const struct iphdr *iph,
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u32 mtu)
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{
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struct dst_entry *dst;
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const struct inet_sock *inet = inet_sk(sk);
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const struct dccp_sock *dp = dccp_sk(sk);
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/* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
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* send out by Linux are always < 576bytes so they should go through
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* unfragmented).
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*/
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if (sk->sk_state == DCCP_LISTEN)
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return;
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/* We don't check in the destentry if pmtu discovery is forbidden
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* on this route. We just assume that no packet_to_big packets
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* are send back when pmtu discovery is not active.
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* There is a small race when the user changes this flag in the
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* route, but I think that's acceptable.
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*/
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if ((dst = __sk_dst_check(sk, 0)) == NULL)
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return;
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dst->ops->update_pmtu(dst, mtu);
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/* Something is about to be wrong... Remember soft error
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* for the case, if this connection will not able to recover.
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*/
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if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
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sk->sk_err_soft = EMSGSIZE;
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mtu = dst_mtu(dst);
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if (inet->pmtudisc != IP_PMTUDISC_DONT &&
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inet_csk(sk)->icsk_pmtu_cookie > mtu) {
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dccp_sync_mss(sk, mtu);
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/*
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* From RFC 4340, sec. 14.1:
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*
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* DCCP-Sync packets are the best choice for upward
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* probing, since DCCP-Sync probes do not risk application
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* data loss.
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*/
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dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
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} /* else let the usual retransmit timer handle it */
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}
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/*
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* This routine is called by the ICMP module when it gets some sort of error
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* condition. If err < 0 then the socket should be closed and the error
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* returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
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* After adjustment header points to the first 8 bytes of the tcp header. We
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* need to find the appropriate port.
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*
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* The locking strategy used here is very "optimistic". When someone else
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* accesses the socket the ICMP is just dropped and for some paths there is no
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* check at all. A more general error queue to queue errors for later handling
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* is probably better.
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*/
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static void dccp_v4_err(struct sk_buff *skb, u32 info)
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{
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const struct iphdr *iph = (struct iphdr *)skb->data;
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const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
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(iph->ihl << 2));
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struct dccp_sock *dp;
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struct inet_sock *inet;
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const int type = icmp_hdr(skb)->type;
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const int code = icmp_hdr(skb)->code;
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struct sock *sk;
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__u64 seq;
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int err;
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if (skb->len < (iph->ihl << 2) + 8) {
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ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
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return;
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}
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sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
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iph->saddr, dh->dccph_sport, inet_iif(skb));
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if (sk == NULL) {
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ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
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return;
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}
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if (sk->sk_state == DCCP_TIME_WAIT) {
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inet_twsk_put(inet_twsk(sk));
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return;
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}
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bh_lock_sock(sk);
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/* If too many ICMPs get dropped on busy
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* servers this needs to be solved differently.
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*/
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if (sock_owned_by_user(sk))
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NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
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if (sk->sk_state == DCCP_CLOSED)
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goto out;
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dp = dccp_sk(sk);
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seq = dccp_hdr_seq(skb);
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if (sk->sk_state != DCCP_LISTEN &&
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!between48(seq, dp->dccps_swl, dp->dccps_swh)) {
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NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
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goto out;
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}
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switch (type) {
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case ICMP_SOURCE_QUENCH:
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/* Just silently ignore these. */
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goto out;
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case ICMP_PARAMETERPROB:
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err = EPROTO;
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break;
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case ICMP_DEST_UNREACH:
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if (code > NR_ICMP_UNREACH)
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goto out;
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if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
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if (!sock_owned_by_user(sk))
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dccp_do_pmtu_discovery(sk, iph, info);
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goto out;
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}
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err = icmp_err_convert[code].errno;
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break;
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case ICMP_TIME_EXCEEDED:
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err = EHOSTUNREACH;
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break;
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default:
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goto out;
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}
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switch (sk->sk_state) {
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struct request_sock *req , **prev;
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case DCCP_LISTEN:
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if (sock_owned_by_user(sk))
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goto out;
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req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
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iph->daddr, iph->saddr);
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if (!req)
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goto out;
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/*
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* ICMPs are not backlogged, hence we cannot get an established
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* socket here.
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*/
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BUG_TRAP(!req->sk);
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if (seq != dccp_rsk(req)->dreq_iss) {
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NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
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goto out;
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}
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/*
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* Still in RESPOND, just remove it silently.
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* There is no good way to pass the error to the newly
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* created socket, and POSIX does not want network
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* errors returned from accept().
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*/
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inet_csk_reqsk_queue_drop(sk, req, prev);
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goto out;
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case DCCP_REQUESTING:
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case DCCP_RESPOND:
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if (!sock_owned_by_user(sk)) {
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DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
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sk->sk_err = err;
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sk->sk_error_report(sk);
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dccp_done(sk);
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} else
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sk->sk_err_soft = err;
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goto out;
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}
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/* If we've already connected we will keep trying
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* until we time out, or the user gives up.
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*
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* rfc1122 4.2.3.9 allows to consider as hard errors
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* only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
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* but it is obsoleted by pmtu discovery).
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*
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* Note, that in modern internet, where routing is unreliable
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* and in each dark corner broken firewalls sit, sending random
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* errors ordered by their masters even this two messages finally lose
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* their original sense (even Linux sends invalid PORT_UNREACHs)
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*
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* Now we are in compliance with RFCs.
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* --ANK (980905)
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*/
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inet = inet_sk(sk);
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if (!sock_owned_by_user(sk) && inet->recverr) {
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sk->sk_err = err;
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sk->sk_error_report(sk);
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} else /* Only an error on timeout */
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sk->sk_err_soft = err;
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out:
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bh_unlock_sock(sk);
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sock_put(sk);
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}
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static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
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__be32 src, __be32 dst)
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{
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return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
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}
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void dccp_v4_send_check(struct sock *sk, int unused, struct sk_buff *skb)
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{
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const struct inet_sock *inet = inet_sk(sk);
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struct dccp_hdr *dh = dccp_hdr(skb);
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dccp_csum_outgoing(skb);
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dh->dccph_checksum = dccp_v4_csum_finish(skb, inet->saddr, inet->daddr);
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}
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EXPORT_SYMBOL_GPL(dccp_v4_send_check);
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|
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static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
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{
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return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
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ip_hdr(skb)->saddr,
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dccp_hdr(skb)->dccph_dport,
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dccp_hdr(skb)->dccph_sport);
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}
|
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|
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/*
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* The three way handshake has completed - we got a valid ACK or DATAACK -
|
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* now create the new socket.
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*
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* This is the equivalent of TCP's tcp_v4_syn_recv_sock
|
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*/
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struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
|
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struct request_sock *req,
|
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struct dst_entry *dst)
|
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{
|
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struct inet_request_sock *ireq;
|
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struct inet_sock *newinet;
|
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struct dccp_sock *newdp;
|
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struct sock *newsk;
|
|
|
|
if (sk_acceptq_is_full(sk))
|
|
goto exit_overflow;
|
|
|
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if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
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|
goto exit;
|
|
|
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newsk = dccp_create_openreq_child(sk, req, skb);
|
|
if (newsk == NULL)
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goto exit;
|
|
|
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sk_setup_caps(newsk, dst);
|
|
|
|
newdp = dccp_sk(newsk);
|
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newinet = inet_sk(newsk);
|
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ireq = inet_rsk(req);
|
|
newinet->daddr = ireq->rmt_addr;
|
|
newinet->rcv_saddr = ireq->loc_addr;
|
|
newinet->saddr = ireq->loc_addr;
|
|
newinet->opt = ireq->opt;
|
|
ireq->opt = NULL;
|
|
newinet->mc_index = inet_iif(skb);
|
|
newinet->mc_ttl = ip_hdr(skb)->ttl;
|
|
newinet->id = jiffies;
|
|
|
|
dccp_sync_mss(newsk, dst_mtu(dst));
|
|
|
|
__inet_hash(&dccp_hashinfo, newsk, 0);
|
|
__inet_inherit_port(&dccp_hashinfo, sk, newsk);
|
|
|
|
return newsk;
|
|
|
|
exit_overflow:
|
|
NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
|
|
exit:
|
|
NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
|
|
dst_release(dst);
|
|
return NULL;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
|
|
|
|
static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
const struct dccp_hdr *dh = dccp_hdr(skb);
|
|
const struct iphdr *iph = ip_hdr(skb);
|
|
struct sock *nsk;
|
|
struct request_sock **prev;
|
|
/* Find possible connection requests. */
|
|
struct request_sock *req = inet_csk_search_req(sk, &prev,
|
|
dh->dccph_sport,
|
|
iph->saddr, iph->daddr);
|
|
if (req != NULL)
|
|
return dccp_check_req(sk, skb, req, prev);
|
|
|
|
nsk = inet_lookup_established(&dccp_hashinfo,
|
|
iph->saddr, dh->dccph_sport,
|
|
iph->daddr, dh->dccph_dport,
|
|
inet_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 struct dst_entry* dccp_v4_route_skb(struct sock *sk,
|
|
struct sk_buff *skb)
|
|
{
|
|
struct rtable *rt;
|
|
struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
|
|
.nl_u = { .ip4_u =
|
|
{ .daddr = ip_hdr(skb)->saddr,
|
|
.saddr = ip_hdr(skb)->daddr,
|
|
.tos = RT_CONN_FLAGS(sk) } },
|
|
.proto = sk->sk_protocol,
|
|
.uli_u = { .ports =
|
|
{ .sport = dccp_hdr(skb)->dccph_dport,
|
|
.dport = dccp_hdr(skb)->dccph_sport }
|
|
}
|
|
};
|
|
|
|
security_skb_classify_flow(skb, &fl);
|
|
if (ip_route_output_flow(&rt, &fl, sk, 0)) {
|
|
IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
|
|
return NULL;
|
|
}
|
|
|
|
return &rt->u.dst;
|
|
}
|
|
|
|
static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
|
|
struct dst_entry *dst)
|
|
{
|
|
int err = -1;
|
|
struct sk_buff *skb;
|
|
|
|
/* First, grab a route. */
|
|
|
|
if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
|
|
goto out;
|
|
|
|
skb = dccp_make_response(sk, dst, req);
|
|
if (skb != NULL) {
|
|
const struct inet_request_sock *ireq = inet_rsk(req);
|
|
struct dccp_hdr *dh = dccp_hdr(skb);
|
|
|
|
dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
|
|
ireq->rmt_addr);
|
|
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
|
|
err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
|
|
ireq->rmt_addr,
|
|
ireq->opt);
|
|
err = net_xmit_eval(err);
|
|
}
|
|
|
|
out:
|
|
dst_release(dst);
|
|
return err;
|
|
}
|
|
|
|
static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
|
|
{
|
|
int err;
|
|
struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
|
|
const struct iphdr *rxiph;
|
|
const int dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
|
|
sizeof(struct dccp_hdr_ext) +
|
|
sizeof(struct dccp_hdr_reset);
|
|
struct sk_buff *skb;
|
|
struct dst_entry *dst;
|
|
u64 seqno = 0;
|
|
|
|
/* Never send a reset in response to a reset. */
|
|
if (rxdh->dccph_type == DCCP_PKT_RESET)
|
|
return;
|
|
|
|
if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
|
|
return;
|
|
|
|
dst = dccp_v4_route_skb(dccp_v4_ctl_socket->sk, rxskb);
|
|
if (dst == NULL)
|
|
return;
|
|
|
|
skb = alloc_skb(dccp_v4_ctl_socket->sk->sk_prot->max_header,
|
|
GFP_ATOMIC);
|
|
if (skb == NULL)
|
|
goto out;
|
|
|
|
/* Reserve space for headers. */
|
|
skb_reserve(skb, dccp_v4_ctl_socket->sk->sk_prot->max_header);
|
|
skb->dst = dst_clone(dst);
|
|
|
|
dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
|
|
|
|
/* Build DCCP header and checksum it. */
|
|
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);
|
|
rxiph = ip_hdr(rxskb);
|
|
dh->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
|
|
rxiph->daddr);
|
|
|
|
bh_lock_sock(dccp_v4_ctl_socket->sk);
|
|
err = ip_build_and_send_pkt(skb, dccp_v4_ctl_socket->sk,
|
|
rxiph->daddr, rxiph->saddr, NULL);
|
|
bh_unlock_sock(dccp_v4_ctl_socket->sk);
|
|
|
|
if (net_xmit_eval(err) == 0) {
|
|
DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
|
|
DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
|
|
}
|
|
out:
|
|
dst_release(dst);
|
|
}
|
|
|
|
static void dccp_v4_reqsk_destructor(struct request_sock *req)
|
|
{
|
|
kfree(inet_rsk(req)->opt);
|
|
}
|
|
|
|
static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
|
|
.family = PF_INET,
|
|
.obj_size = sizeof(struct dccp_request_sock),
|
|
.rtx_syn_ack = dccp_v4_send_response,
|
|
.send_ack = dccp_reqsk_send_ack,
|
|
.destructor = dccp_v4_reqsk_destructor,
|
|
.send_reset = dccp_v4_ctl_send_reset,
|
|
};
|
|
|
|
int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
struct inet_request_sock *ireq;
|
|
struct request_sock *req;
|
|
struct dccp_request_sock *dreq;
|
|
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;
|
|
|
|
/* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
|
|
if (((struct rtable *)skb->dst)->rt_flags &
|
|
(RTCF_BROADCAST | RTCF_MULTICAST)) {
|
|
reset_code = DCCP_RESET_CODE_NO_CONNECTION;
|
|
goto drop;
|
|
}
|
|
|
|
if (dccp_bad_service_code(sk, service)) {
|
|
reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
|
|
goto drop;
|
|
}
|
|
/*
|
|
* TW buckets are converted to open requests without
|
|
* limitations, they conserve resources and peer is
|
|
* evidently real one.
|
|
*/
|
|
if (inet_csk_reqsk_queue_is_full(sk))
|
|
goto drop;
|
|
|
|
/*
|
|
* Accept backlog is full. If we have already queued enough
|
|
* of warm entries in syn queue, drop request. It is better than
|
|
* clogging syn queue with openreqs with exponentially increasing
|
|
* timeout.
|
|
*/
|
|
if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
|
|
goto drop;
|
|
|
|
req = reqsk_alloc(&dccp_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;
|
|
|
|
ireq = inet_rsk(req);
|
|
ireq->loc_addr = ip_hdr(skb)->daddr;
|
|
ireq->rmt_addr = ip_hdr(skb)->saddr;
|
|
ireq->opt = NULL;
|
|
|
|
/*
|
|
* 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_v4_init_sequence(skb);
|
|
dreq->dreq_service = service;
|
|
|
|
if (dccp_v4_send_response(sk, req, NULL))
|
|
goto drop_and_free;
|
|
|
|
inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
|
|
return 0;
|
|
|
|
drop_and_free:
|
|
reqsk_free(req);
|
|
drop:
|
|
DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
|
|
dcb->dccpd_reset_code = reset_code;
|
|
return -1;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
|
|
|
|
int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
struct dccp_hdr *dh = dccp_hdr(skb);
|
|
|
|
if (sk->sk_state == DCCP_OPEN) { /* Fast path */
|
|
if (dccp_rcv_established(sk, skb, dh, skb->len))
|
|
goto reset;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Step 3: Process LISTEN state
|
|
* 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_v4_hnd_req(sk, skb);
|
|
|
|
if (nsk == NULL)
|
|
goto discard;
|
|
|
|
if (nsk != sk) {
|
|
if (dccp_child_process(sk, nsk, skb))
|
|
goto reset;
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
if (dccp_rcv_state_process(sk, skb, dh, skb->len))
|
|
goto reset;
|
|
return 0;
|
|
|
|
reset:
|
|
dccp_v4_ctl_send_reset(sk, skb);
|
|
discard:
|
|
kfree_skb(skb);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
|
|
|
|
/**
|
|
* dccp_invalid_packet - check for malformed packets
|
|
* Implements RFC 4340, 8.5: Step 1: Check header basics
|
|
* Packets that fail these checks are ignored and do not receive Resets.
|
|
*/
|
|
int dccp_invalid_packet(struct sk_buff *skb)
|
|
{
|
|
const struct dccp_hdr *dh;
|
|
unsigned int cscov;
|
|
|
|
if (skb->pkt_type != PACKET_HOST)
|
|
return 1;
|
|
|
|
/* If the packet is shorter than 12 bytes, drop packet and return */
|
|
if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
|
|
DCCP_WARN("pskb_may_pull failed\n");
|
|
return 1;
|
|
}
|
|
|
|
dh = dccp_hdr(skb);
|
|
|
|
/* If P.type is not understood, drop packet and return */
|
|
if (dh->dccph_type >= DCCP_PKT_INVALID) {
|
|
DCCP_WARN("invalid packet type\n");
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* If P.Data Offset is too small for packet type, drop packet and return
|
|
*/
|
|
if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
|
|
DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
|
|
return 1;
|
|
}
|
|
/*
|
|
* If P.Data Offset is too too large for packet, drop packet and return
|
|
*/
|
|
if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
|
|
DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
|
|
* has short sequence numbers), drop packet and return
|
|
*/
|
|
if (dh->dccph_type >= DCCP_PKT_DATA &&
|
|
dh->dccph_type <= DCCP_PKT_DATAACK && dh->dccph_x == 0) {
|
|
DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
|
|
dccp_packet_name(dh->dccph_type));
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* If P.CsCov is too large for the packet size, drop packet and return.
|
|
* This must come _before_ checksumming (not as RFC 4340 suggests).
|
|
*/
|
|
cscov = dccp_csum_coverage(skb);
|
|
if (cscov > skb->len) {
|
|
DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
|
|
dh->dccph_cscov, skb->len);
|
|
return 1;
|
|
}
|
|
|
|
/* If header checksum is incorrect, drop packet and return.
|
|
* (This step is completed in the AF-dependent functions.) */
|
|
skb->csum = skb_checksum(skb, 0, cscov, 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(dccp_invalid_packet);
|
|
|
|
/* this is called when real data arrives */
|
|
static int dccp_v4_rcv(struct sk_buff *skb)
|
|
{
|
|
const struct dccp_hdr *dh;
|
|
const struct iphdr *iph;
|
|
struct sock *sk;
|
|
int min_cov;
|
|
|
|
/* Step 1: Check header basics */
|
|
|
|
if (dccp_invalid_packet(skb))
|
|
goto discard_it;
|
|
|
|
iph = ip_hdr(skb);
|
|
/* Step 1: If header checksum is incorrect, drop packet and return */
|
|
if (dccp_v4_csum_finish(skb, iph->saddr, iph->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;
|
|
|
|
dccp_pr_debug("%8.8s "
|
|
"src=%u.%u.%u.%u@%-5d "
|
|
"dst=%u.%u.%u.%u@%-5d seq=%llu",
|
|
dccp_packet_name(dh->dccph_type),
|
|
NIPQUAD(iph->saddr), ntohs(dh->dccph_sport),
|
|
NIPQUAD(iph->daddr), ntohs(dh->dccph_dport),
|
|
(unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
|
|
|
|
if (dccp_packet_without_ack(skb)) {
|
|
DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
|
|
dccp_pr_debug_cat("\n");
|
|
} else {
|
|
DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
|
|
dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
|
|
DCCP_SKB_CB(skb)->dccpd_ack_seq);
|
|
}
|
|
|
|
/* Step 2:
|
|
* Look up flow ID in table and get corresponding socket */
|
|
sk = __inet_lookup(&dccp_hashinfo,
|
|
iph->saddr, dh->dccph_sport,
|
|
iph->daddr, dh->dccph_dport, inet_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: "Such packets SHOULD be reported using Data Dropped
|
|
* options (Section 11.7) with Drop Code 0, Protocol
|
|
* Constraints." */
|
|
goto discard_and_relse;
|
|
}
|
|
|
|
if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
|
|
goto discard_and_relse;
|
|
nf_reset(skb);
|
|
|
|
return sk_receive_skb(sk, skb, 1);
|
|
|
|
no_dccp_socket:
|
|
if (!xfrm4_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_v4_ctl_send_reset(sk, skb);
|
|
}
|
|
|
|
discard_it:
|
|
kfree_skb(skb);
|
|
return 0;
|
|
|
|
discard_and_relse:
|
|
sock_put(sk);
|
|
goto discard_it;
|
|
}
|
|
|
|
static struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
|
|
.queue_xmit = ip_queue_xmit,
|
|
.send_check = dccp_v4_send_check,
|
|
.rebuild_header = inet_sk_rebuild_header,
|
|
.conn_request = dccp_v4_conn_request,
|
|
.syn_recv_sock = dccp_v4_request_recv_sock,
|
|
.net_header_len = sizeof(struct iphdr),
|
|
.setsockopt = ip_setsockopt,
|
|
.getsockopt = ip_getsockopt,
|
|
.addr2sockaddr = inet_csk_addr2sockaddr,
|
|
.sockaddr_len = sizeof(struct sockaddr_in),
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_setsockopt = compat_ip_setsockopt,
|
|
.compat_getsockopt = compat_ip_getsockopt,
|
|
#endif
|
|
};
|
|
|
|
static int dccp_v4_init_sock(struct sock *sk)
|
|
{
|
|
static __u8 dccp_v4_ctl_sock_initialized;
|
|
int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
|
|
|
|
if (err == 0) {
|
|
if (unlikely(!dccp_v4_ctl_sock_initialized))
|
|
dccp_v4_ctl_sock_initialized = 1;
|
|
inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static struct timewait_sock_ops dccp_timewait_sock_ops = {
|
|
.twsk_obj_size = sizeof(struct inet_timewait_sock),
|
|
};
|
|
|
|
static struct proto dccp_v4_prot = {
|
|
.name = "DCCP",
|
|
.owner = THIS_MODULE,
|
|
.close = dccp_close,
|
|
.connect = dccp_v4_connect,
|
|
.disconnect = dccp_disconnect,
|
|
.ioctl = dccp_ioctl,
|
|
.init = dccp_v4_init_sock,
|
|
.setsockopt = dccp_setsockopt,
|
|
.getsockopt = dccp_getsockopt,
|
|
.sendmsg = dccp_sendmsg,
|
|
.recvmsg = dccp_recvmsg,
|
|
.backlog_rcv = dccp_v4_do_rcv,
|
|
.hash = dccp_hash,
|
|
.unhash = dccp_unhash,
|
|
.accept = inet_csk_accept,
|
|
.get_port = dccp_v4_get_port,
|
|
.shutdown = dccp_shutdown,
|
|
.destroy = dccp_destroy_sock,
|
|
.orphan_count = &dccp_orphan_count,
|
|
.max_header = MAX_DCCP_HEADER,
|
|
.obj_size = sizeof(struct dccp_sock),
|
|
.rsk_prot = &dccp_request_sock_ops,
|
|
.twsk_prot = &dccp_timewait_sock_ops,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_setsockopt = compat_dccp_setsockopt,
|
|
.compat_getsockopt = compat_dccp_getsockopt,
|
|
#endif
|
|
};
|
|
|
|
static struct net_protocol dccp_v4_protocol = {
|
|
.handler = dccp_v4_rcv,
|
|
.err_handler = dccp_v4_err,
|
|
.no_policy = 1,
|
|
};
|
|
|
|
static const struct proto_ops inet_dccp_ops = {
|
|
.family = PF_INET,
|
|
.owner = THIS_MODULE,
|
|
.release = inet_release,
|
|
.bind = inet_bind,
|
|
.connect = inet_stream_connect,
|
|
.socketpair = sock_no_socketpair,
|
|
.accept = inet_accept,
|
|
.getname = inet_getname,
|
|
/* FIXME: work on tcp_poll to rename it to inet_csk_poll */
|
|
.poll = dccp_poll,
|
|
.ioctl = inet_ioctl,
|
|
/* FIXME: work on inet_listen to rename it to sock_common_listen */
|
|
.listen = inet_dccp_listen,
|
|
.shutdown = inet_shutdown,
|
|
.setsockopt = sock_common_setsockopt,
|
|
.getsockopt = sock_common_getsockopt,
|
|
.sendmsg = inet_sendmsg,
|
|
.recvmsg = sock_common_recvmsg,
|
|
.mmap = sock_no_mmap,
|
|
.sendpage = sock_no_sendpage,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_setsockopt = compat_sock_common_setsockopt,
|
|
.compat_getsockopt = compat_sock_common_getsockopt,
|
|
#endif
|
|
};
|
|
|
|
static struct inet_protosw dccp_v4_protosw = {
|
|
.type = SOCK_DCCP,
|
|
.protocol = IPPROTO_DCCP,
|
|
.prot = &dccp_v4_prot,
|
|
.ops = &inet_dccp_ops,
|
|
.capability = -1,
|
|
.no_check = 0,
|
|
.flags = INET_PROTOSW_ICSK,
|
|
};
|
|
|
|
static int __init dccp_v4_init(void)
|
|
{
|
|
int err = proto_register(&dccp_v4_prot, 1);
|
|
|
|
if (err != 0)
|
|
goto out;
|
|
|
|
err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
|
|
if (err != 0)
|
|
goto out_proto_unregister;
|
|
|
|
inet_register_protosw(&dccp_v4_protosw);
|
|
|
|
err = inet_csk_ctl_sock_create(&dccp_v4_ctl_socket, PF_INET,
|
|
SOCK_DCCP, IPPROTO_DCCP);
|
|
if (err)
|
|
goto out_unregister_protosw;
|
|
out:
|
|
return err;
|
|
out_unregister_protosw:
|
|
inet_unregister_protosw(&dccp_v4_protosw);
|
|
inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
|
|
out_proto_unregister:
|
|
proto_unregister(&dccp_v4_prot);
|
|
goto out;
|
|
}
|
|
|
|
static void __exit dccp_v4_exit(void)
|
|
{
|
|
inet_unregister_protosw(&dccp_v4_protosw);
|
|
inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
|
|
proto_unregister(&dccp_v4_prot);
|
|
}
|
|
|
|
module_init(dccp_v4_init);
|
|
module_exit(dccp_v4_exit);
|
|
|
|
/*
|
|
* __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
|
|
* values directly, Also cover the case where the protocol is not specified,
|
|
* i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
|
|
*/
|
|
MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-33-type-6");
|
|
MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-0-type-6");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
|
|
MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");
|