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remarkable-linux/net/dccp/ipv4.c
Arnaldo Carvalho de Melo 14c850212e [INET_SOCK]: Move struct inet_sock & helper functions to net/inet_sock.h 
To help in reducing the number of include dependencies, several files were
touched as they were getting needed headers indirectly for stuff they use.

Thanks also to Alan Menegotto for pointing out that net/dccp/proto.c had
linux/dccp.h include twice.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:11:21 -08:00

1170 lines
30 KiB
C
Raw Blame History

/*
* net/dccp/ipv4.c
*
* An implementation of the DCCP protocol
* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* 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/config.h>
#include <linux/dccp.h>
#include <linux/icmp.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/random.h>
#include <net/icmp.h>
#include <net/inet_hashtables.h>
#include <net/inet_sock.h>
#include <net/sock.h>
#include <net/timewait_sock.h>
#include <net/tcp_states.h>
#include <net/xfrm.h>
#include "ackvec.h"
#include "ccid.h"
#include "dccp.h"
struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
.lhash_lock = RW_LOCK_UNLOCKED,
.lhash_users = ATOMIC_INIT(0),
.lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
};
EXPORT_SYMBOL_GPL(dccp_hashinfo);
static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
{
return inet_csk_get_port(&dccp_hashinfo, sk, snum,
inet_csk_bind_conflict);
}
static void dccp_v4_hash(struct sock *sk)
{
inet_hash(&dccp_hashinfo, sk);
}
void dccp_unhash(struct sock *sk)
{
inet_unhash(&dccp_hashinfo, sk);
}
EXPORT_SYMBOL_GPL(dccp_unhash);
int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
struct inet_sock *inet = inet_sk(sk);
struct dccp_sock *dp = dccp_sk(sk);
const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
struct rtable *rt;
u32 daddr, nexthop;
int tmp;
int err;
dp->dccps_role = DCCP_ROLE_CLIENT;
if (dccp_service_not_initialized(sk))
return -EPROTO;
if (addr_len < sizeof(struct sockaddr_in))
return -EINVAL;
if (usin->sin_family != AF_INET)
return -EAFNOSUPPORT;
nexthop = daddr = usin->sin_addr.s_addr;
if (inet->opt != NULL && inet->opt->srr) {
if (daddr == 0)
return -EINVAL;
nexthop = inet->opt->faddr;
}
tmp = ip_route_connect(&rt, nexthop, inet->saddr,
RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
IPPROTO_DCCP,
inet->sport, usin->sin_port, sk);
if (tmp < 0)
return tmp;
if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
ip_rt_put(rt);
return -ENETUNREACH;
}
if (inet->opt == NULL || !inet->opt->srr)
daddr = rt->rt_dst;
if (inet->saddr == 0)
inet->saddr = rt->rt_src;
inet->rcv_saddr = inet->saddr;
inet->dport = usin->sin_port;
inet->daddr = daddr;
inet_csk(sk)->icsk_ext_hdr_len = 0;
if (inet->opt != NULL)
inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
/*
* Socket identity is still unknown (sport may be zero).
* However we set state to DCCP_REQUESTING and not releasing socket
* lock select source port, enter ourselves into the hash tables and
* complete initialization after this.
*/
dccp_set_state(sk, DCCP_REQUESTING);
err = inet_hash_connect(&dccp_death_row, sk);
if (err != 0)
goto failure;
err = ip_route_newports(&rt, inet->sport, inet->dport, sk);
if (err != 0)
goto failure;
/* OK, now commit destination to socket. */
sk_setup_caps(sk, &rt->u.dst);
dp->dccps_gar =
dp->dccps_iss = secure_dccp_sequence_number(inet->saddr,
inet->daddr,
inet->sport,
usin->sin_port);
dccp_update_gss(sk, dp->dccps_iss);
inet->id = dp->dccps_iss ^ jiffies;
err = dccp_connect(sk);
rt = NULL;
if (err != 0)
goto failure;
out:
return err;
failure:
/*
* This unhashes the socket and releases the local port, if necessary.
*/
dccp_set_state(sk, DCCP_CLOSED);
ip_rt_put(rt);
sk->sk_route_caps = 0;
inet->dport = 0;
goto out;
}
EXPORT_SYMBOL_GPL(dccp_v4_connect);
/*
* This routine does path mtu discovery as defined in RFC1191.
*/
static inline void dccp_do_pmtu_discovery(struct sock *sk,
const struct iphdr *iph,
u32 mtu)
{
struct dst_entry *dst;
const struct inet_sock *inet = inet_sk(sk);
const struct dccp_sock *dp = dccp_sk(sk);
/* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
* send out by Linux are always < 576bytes so they should go through
* unfragmented).
*/
if (sk->sk_state == DCCP_LISTEN)
return;
/* We don't check in the destentry if pmtu discovery is forbidden
* on this route. We just assume that no packet_to_big packets
* are send back when pmtu discovery is not active.
* There is a small race when the user changes this flag in the
* route, but I think that's acceptable.
*/
if ((dst = __sk_dst_check(sk, 0)) == NULL)
return;
dst->ops->update_pmtu(dst, mtu);
/* Something is about to be wrong... Remember soft error
* for the case, if this connection will not able to recover.
*/
if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
sk->sk_err_soft = EMSGSIZE;
mtu = dst_mtu(dst);
if (inet->pmtudisc != IP_PMTUDISC_DONT &&
inet_csk(sk)->icsk_pmtu_cookie > mtu) {
dccp_sync_mss(sk, mtu);
/*
* From: draft-ietf-dccp-spec-11.txt
*
* DCCP-Sync packets are the best choice for upward
* probing, since DCCP-Sync probes do not risk application
* data loss.
*/
dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
} /* else let the usual retransmit timer handle it */
}
static void dccp_v4_ctl_send_ack(struct sk_buff *rxskb)
{
int err;
struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
const int dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_ack_bits);
struct sk_buff *skb;
if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
return;
skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
if (skb == NULL)
return;
/* Reserve space for headers. */
skb_reserve(skb, MAX_DCCP_HEADER);
skb->dst = dst_clone(rxskb->dst);
skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
dh = dccp_hdr(skb);
memset(dh, 0, dccp_hdr_ack_len);
/* Build DCCP header and checksum it. */
dh->dccph_type = DCCP_PKT_ACK;
dh->dccph_sport = rxdh->dccph_dport;
dh->dccph_dport = rxdh->dccph_sport;
dh->dccph_doff = dccp_hdr_ack_len / 4;
dh->dccph_x = 1;
dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq);
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
DCCP_SKB_CB(rxskb)->dccpd_seq);
bh_lock_sock(dccp_ctl_socket->sk);
err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
rxskb->nh.iph->daddr,
rxskb->nh.iph->saddr, NULL);
bh_unlock_sock(dccp_ctl_socket->sk);
if (err == NET_XMIT_CN || err == 0) {
DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
}
}
static void dccp_v4_reqsk_send_ack(struct sk_buff *skb,
struct request_sock *req)
{
dccp_v4_ctl_send_ack(skb);
}
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);
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);
if (err == NET_XMIT_CN)
err = 0;
}
out:
dst_release(dst);
return err;
}
/*
* This routine is called by the ICMP module when it gets some sort of error
* condition. If err < 0 then the socket should be closed and the error
* returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
* After adjustment header points to the first 8 bytes of the tcp header. We
* need to find the appropriate port.
*
* The locking strategy used here is very "optimistic". When someone else
* accesses the socket the ICMP is just dropped and for some paths there is no
* check at all. A more general error queue to queue errors for later handling
* is probably better.
*/
void dccp_v4_err(struct sk_buff *skb, u32 info)
{
const struct iphdr *iph = (struct iphdr *)skb->data;
const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
(iph->ihl << 2));
struct dccp_sock *dp;
struct inet_sock *inet;
const int type = skb->h.icmph->type;
const int code = skb->h.icmph->code;
struct sock *sk;
__u64 seq;
int err;
if (skb->len < (iph->ihl << 2) + 8) {
ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
return;
}
sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
iph->saddr, dh->dccph_sport, inet_iif(skb));
if (sk == NULL) {
ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
return;
}
if (sk->sk_state == DCCP_TIME_WAIT) {
inet_twsk_put((struct inet_timewait_sock *)sk);
return;
}
bh_lock_sock(sk);
/* If too many ICMPs get dropped on busy
* servers this needs to be solved differently.
*/
if (sock_owned_by_user(sk))
NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
if (sk->sk_state == DCCP_CLOSED)
goto out;
dp = dccp_sk(sk);
seq = dccp_hdr_seq(skb);
if (sk->sk_state != DCCP_LISTEN &&
!between48(seq, dp->dccps_swl, dp->dccps_swh)) {
NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
goto out;
}
switch (type) {
case ICMP_SOURCE_QUENCH:
/* Just silently ignore these. */
goto out;
case ICMP_PARAMETERPROB:
err = EPROTO;
break;
case ICMP_DEST_UNREACH:
if (code > NR_ICMP_UNREACH)
goto out;
if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
if (!sock_owned_by_user(sk))
dccp_do_pmtu_discovery(sk, iph, info);
goto out;
}
err = icmp_err_convert[code].errno;
break;
case ICMP_TIME_EXCEEDED:
err = EHOSTUNREACH;
break;
default:
goto out;
}
switch (sk->sk_state) {
struct request_sock *req , **prev;
case DCCP_LISTEN:
if (sock_owned_by_user(sk))
goto out;
req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
iph->daddr, iph->saddr);
if (!req)
goto out;
/*
* ICMPs are not backlogged, hence we cannot get an established
* socket here.
*/
BUG_TRAP(!req->sk);
if (seq != dccp_rsk(req)->dreq_iss) {
NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
goto out;
}
/*
* Still in RESPOND, just remove it silently.
* There is no good way to pass the error to the newly
* created socket, and POSIX does not want network
* errors returned from accept().
*/
inet_csk_reqsk_queue_drop(sk, req, prev);
goto out;
case DCCP_REQUESTING:
case DCCP_RESPOND:
if (!sock_owned_by_user(sk)) {
DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
sk->sk_err = err;
sk->sk_error_report(sk);
dccp_done(sk);
} else
sk->sk_err_soft = err;
goto out;
}
/* If we've already connected we will keep trying
* until we time out, or the user gives up.
*
* rfc1122 4.2.3.9 allows to consider as hard errors
* only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
* but it is obsoleted by pmtu discovery).
*
* Note, that in modern internet, where routing is unreliable
* and in each dark corner broken firewalls sit, sending random
* errors ordered by their masters even this two messages finally lose
* their original sense (even Linux sends invalid PORT_UNREACHs)
*
* Now we are in compliance with RFCs.
* --ANK (980905)
*/
inet = inet_sk(sk);
if (!sock_owned_by_user(sk) && inet->recverr) {
sk->sk_err = err;
sk->sk_error_report(sk);
} else /* Only an error on timeout */
sk->sk_err_soft = err;
out:
bh_unlock_sock(sk);
sock_put(sk);
}
/* This routine computes an IPv4 DCCP checksum. */
void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
{
const struct inet_sock *inet = inet_sk(sk);
struct dccp_hdr *dh = dccp_hdr(skb);
dh->dccph_checksum = dccp_v4_checksum(skb, inet->saddr, inet->daddr);
}
EXPORT_SYMBOL_GPL(dccp_v4_send_check);
int dccp_v4_send_reset(struct sock *sk, enum dccp_reset_codes code)
{
struct sk_buff *skb;
/*
* FIXME: what if rebuild_header fails?
* Should we be doing a rebuild_header here?
*/
int err = inet_sk_rebuild_header(sk);
if (err != 0)
return err;
skb = dccp_make_reset(sk, sk->sk_dst_cache, code);
if (skb != NULL) {
const struct inet_sock *inet = inet_sk(sk);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
err = ip_build_and_send_pkt(skb, sk,
inet->saddr, inet->daddr, NULL);
if (err == NET_XMIT_CN)
err = 0;
}
return err;
}
static inline u64 dccp_v4_init_sequence(const struct sock *sk,
const struct sk_buff *skb)
{
return secure_dccp_sequence_number(skb->nh.iph->daddr,
skb->nh.iph->saddr,
dccp_hdr(skb)->dccph_dport,
dccp_hdr(skb)->dccph_sport);
}
int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
{
struct inet_request_sock *ireq;
struct dccp_sock dp;
struct request_sock *req;
struct dccp_request_sock *dreq;
const __u32 saddr = skb->nh.iph->saddr;
const __u32 daddr = skb->nh.iph->daddr;
const __u32 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(sk->sk_prot->rsk_prot);
if (req == NULL)
goto drop;
/* FIXME: process options */
dccp_openreq_init(req, &dp, skb);
ireq = inet_rsk(req);
ireq->loc_addr = daddr;
ireq->rmt_addr = saddr;
req->rcv_wnd = 100; /* Fake, option parsing will get the
right value */
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(sk, 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);
/*
* The three way handshake has completed - we got a valid ACK or DATAACK -
* now create the new socket.
*
* This is the equivalent of TCP's tcp_v4_syn_recv_sock
*/
struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
struct request_sock *req,
struct dst_entry *dst)
{
struct inet_request_sock *ireq;
struct inet_sock *newinet;
struct dccp_sock *newdp;
struct sock *newsk;
if (sk_acceptq_is_full(sk))
goto exit_overflow;
if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
goto exit;
newsk = dccp_create_openreq_child(sk, req, skb);
if (newsk == NULL)
goto exit;
sk_setup_caps(newsk, dst);
newdp = dccp_sk(newsk);
newinet = inet_sk(newsk);
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 = skb->nh.iph->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 = skb->nh.iph;
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, ntohs(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((struct inet_timewait_sock *)nsk);
return NULL;
}
return sk;
}
int dccp_v4_checksum(const struct sk_buff *skb, const u32 saddr,
const u32 daddr)
{
const struct dccp_hdr* dh = dccp_hdr(skb);
int checksum_len;
u32 tmp;
if (dh->dccph_cscov == 0)
checksum_len = skb->len;
else {
checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
checksum_len = checksum_len < skb->len ? checksum_len :
skb->len;
}
tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
return csum_tcpudp_magic(saddr, daddr, checksum_len,
IPPROTO_DCCP, tmp);
}
static int dccp_v4_verify_checksum(struct sk_buff *skb,
const u32 saddr, const u32 daddr)
{
struct dccp_hdr *dh = dccp_hdr(skb);
int checksum_len;
u32 tmp;
if (dh->dccph_cscov == 0)
checksum_len = skb->len;
else {
checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
checksum_len = checksum_len < skb->len ? checksum_len :
skb->len;
}
tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
return csum_tcpudp_magic(saddr, daddr, checksum_len,
IPPROTO_DCCP, tmp) == 0 ? 0 : -1;
}
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 = skb->nh.iph->saddr,
.saddr = skb->nh.iph->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 }
}
};
if (ip_route_output_flow(&rt, &fl, sk, 0)) {
IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
return NULL;
}
return &rt->u.dst;
}
static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
{
int err;
struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
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;
/* 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_ctl_socket->sk, rxskb);
if (dst == NULL)
return;
skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
if (skb == NULL)
goto out;
/* Reserve space for headers. */
skb_reserve(skb, MAX_DCCP_HEADER);
skb->dst = dst_clone(dst);
skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
dh = dccp_hdr(skb);
memset(dh, 0, 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 draft-ietf-dccp-spec-11 */
seqno = 0;
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);
dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
rxskb->nh.iph->daddr);
bh_lock_sock(dccp_ctl_socket->sk);
err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
rxskb->nh.iph->daddr,
rxskb->nh.iph->saddr, NULL);
bh_unlock_sock(dccp_ctl_socket->sk);
if (err == NET_XMIT_CN || err == 0) {
DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
}
out:
dst_release(dst);
}
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 S.state == LISTEN,
* If P.type == Request or P contains a valid Init Cookie
* option,
* * Must scan the packet's options to check for an Init
* Cookie. Only the Init Cookie is 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 Cookie
* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
* 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(skb);
discard:
kfree_skb(skb);
return 0;
}
EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
int dccp_invalid_packet(struct sk_buff *skb)
{
const struct dccp_hdr *dh;
if (skb->pkt_type != PACKET_HOST)
return 1;
if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
return 1;
}
dh = dccp_hdr(skb);
/* If the packet type is not understood, drop packet and return */
if (dh->dccph_type >= DCCP_PKT_INVALID) {
LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
return 1;
}
/*
* If P.Data Offset is too small for packet type, or too large for
* packet, drop packet and return
*/
if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
"too small 1\n",
dh->dccph_doff);
return 1;
}
if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
"too small 2\n",
dh->dccph_doff);
return 1;
}
dh = dccp_hdr(skb);
/*
* 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_x == 0 &&
dh->dccph_type != DCCP_PKT_DATA &&
dh->dccph_type != DCCP_PKT_ACK &&
dh->dccph_type != DCCP_PKT_DATAACK) {
LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
"nor DataAck and P.X == 0\n",
dccp_packet_name(dh->dccph_type));
return 1;
}
return 0;
}
EXPORT_SYMBOL_GPL(dccp_invalid_packet);
/* this is called when real data arrives */
int dccp_v4_rcv(struct sk_buff *skb)
{
const struct dccp_hdr *dh;
struct sock *sk;
/* Step 1: Check header basics: */
if (dccp_invalid_packet(skb))
goto discard_it;
/* If the header checksum is incorrect, drop packet and return */
if (dccp_v4_verify_checksum(skb, skb->nh.iph->saddr,
skb->nh.iph->daddr) < 0) {
LIMIT_NETDEBUG(KERN_WARNING "%s: incorrect header checksum\n",
__FUNCTION__);
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(skb->nh.iph->saddr), ntohs(dh->dccph_sport),
NIPQUAD(skb->nh.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,
skb->nh.iph->saddr, dh->dccph_sport,
skb->nh.iph->daddr, ntohs(dh->dccph_dport),
inet_iif(skb));
/*
* Step 2:
* If no socket ...
* Generate Reset(No Connection) unless P.type == Reset
* Drop packet and return
*/
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");
goto do_time_wait;
}
if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
goto discard_and_relse;
return sk_receive_skb(sk, skb);
no_dccp_socket:
if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
goto discard_it;
/*
* Step 2:
* 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(skb);
}
discard_it:
/* Discard frame. */
kfree_skb(skb);
return 0;
discard_and_relse:
sock_put(sk);
goto discard_it;
do_time_wait:
inet_twsk_put((struct inet_timewait_sock *)sk);
goto no_dccp_socket;
}
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),
};
int dccp_v4_init_sock(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
static int dccp_ctl_socket_init = 1;
dccp_options_init(&dp->dccps_options);
do_gettimeofday(&dp->dccps_epoch);
if (dp->dccps_options.dccpo_send_ack_vector) {
dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(DCCP_MAX_ACKVEC_LEN,
GFP_KERNEL);
if (dp->dccps_hc_rx_ackvec == NULL)
return -ENOMEM;
}
/*
* FIXME: We're hardcoding the CCID, and doing this at this point makes
* the listening (master) sock get CCID control blocks, which is not
* necessary, but for now, to not mess with the test userspace apps,
* lets leave it here, later the real solution is to do this in a
* setsockopt(CCIDs-I-want/accept). -acme
*/
if (likely(!dccp_ctl_socket_init)) {
dp->dccps_hc_rx_ccid = ccid_init(dp->dccps_options.dccpo_rx_ccid,
sk);
dp->dccps_hc_tx_ccid = ccid_init(dp->dccps_options.dccpo_tx_ccid,
sk);
if (dp->dccps_hc_rx_ccid == NULL ||
dp->dccps_hc_tx_ccid == NULL) {
ccid_exit(dp->dccps_hc_rx_ccid, sk);
ccid_exit(dp->dccps_hc_tx_ccid, sk);
if (dp->dccps_options.dccpo_send_ack_vector) {
dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
dp->dccps_hc_rx_ackvec = NULL;
}
dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
return -ENOMEM;
}
} else
dccp_ctl_socket_init = 0;
dccp_init_xmit_timers(sk);
icsk->icsk_rto = DCCP_TIMEOUT_INIT;
sk->sk_state = DCCP_CLOSED;
sk->sk_write_space = dccp_write_space;
icsk->icsk_af_ops = &dccp_ipv4_af_ops;
icsk->icsk_sync_mss = dccp_sync_mss;
dp->dccps_mss_cache = 536;
dp->dccps_role = DCCP_ROLE_UNDEFINED;
dp->dccps_service = DCCP_SERVICE_INVALID_VALUE;
return 0;
}
EXPORT_SYMBOL_GPL(dccp_v4_init_sock);
int dccp_v4_destroy_sock(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
/*
* DCCP doesn't use sk_write_queue, just sk_send_head
* for retransmissions
*/
if (sk->sk_send_head != NULL) {
kfree_skb(sk->sk_send_head);
sk->sk_send_head = NULL;
}
/* Clean up a referenced DCCP bind bucket. */
if (inet_csk(sk)->icsk_bind_hash != NULL)
inet_put_port(&dccp_hashinfo, sk);
kfree(dp->dccps_service_list);
dp->dccps_service_list = NULL;
ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
if (dp->dccps_options.dccpo_send_ack_vector) {
dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
dp->dccps_hc_rx_ackvec = NULL;
}
ccid_exit(dp->dccps_hc_rx_ccid, sk);
ccid_exit(dp->dccps_hc_tx_ccid, sk);
dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
return 0;
}
EXPORT_SYMBOL_GPL(dccp_v4_destroy_sock);
static void dccp_v4_reqsk_destructor(struct request_sock *req)
{
kfree(inet_rsk(req)->opt);
}
static struct request_sock_ops dccp_request_sock_ops = {
.family = PF_INET,
.obj_size = sizeof(struct dccp_request_sock),
.rtx_syn_ack = dccp_v4_send_response,
.send_ack = dccp_v4_reqsk_send_ack,
.destructor = dccp_v4_reqsk_destructor,
.send_reset = dccp_v4_ctl_send_reset,
};
static struct timewait_sock_ops dccp_timewait_sock_ops = {
.twsk_obj_size = sizeof(struct inet_timewait_sock),
};
struct proto dccp_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_v4_hash,
.unhash = dccp_unhash,
.accept = inet_csk_accept,
.get_port = dccp_v4_get_port,
.shutdown = dccp_shutdown,
.destroy = dccp_v4_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,
};
EXPORT_SYMBOL_GPL(dccp_prot);
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