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1347 lines
36 KiB
1347 lines
36 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* SCTP kernel implementation |
|
* Copyright (c) 1999-2000 Cisco, Inc. |
|
* Copyright (c) 1999-2001 Motorola, Inc. |
|
* Copyright (c) 2001-2003 International Business Machines, Corp. |
|
* Copyright (c) 2001 Intel Corp. |
|
* Copyright (c) 2001 Nokia, Inc. |
|
* Copyright (c) 2001 La Monte H.P. Yarroll |
|
* |
|
* This file is part of the SCTP kernel implementation |
|
* |
|
* These functions handle all input from the IP layer into SCTP. |
|
* |
|
* Please send any bug reports or fixes you make to the |
|
* email address(es): |
|
* lksctp developers <[email protected]> |
|
* |
|
* Written or modified by: |
|
* La Monte H.P. Yarroll <[email protected]> |
|
* Karl Knutson <[email protected]> |
|
* Xingang Guo <[email protected]> |
|
* Jon Grimm <[email protected]> |
|
* Hui Huang <[email protected]> |
|
* Daisy Chang <[email protected]> |
|
* Sridhar Samudrala <[email protected]> |
|
* Ardelle Fan <[email protected]> |
|
*/ |
|
|
|
#include <linux/types.h> |
|
#include <linux/list.h> /* For struct list_head */ |
|
#include <linux/socket.h> |
|
#include <linux/ip.h> |
|
#include <linux/time.h> /* For struct timeval */ |
|
#include <linux/slab.h> |
|
#include <net/ip.h> |
|
#include <net/icmp.h> |
|
#include <net/snmp.h> |
|
#include <net/sock.h> |
|
#include <net/xfrm.h> |
|
#include <net/sctp/sctp.h> |
|
#include <net/sctp/sm.h> |
|
#include <net/sctp/checksum.h> |
|
#include <net/net_namespace.h> |
|
#include <linux/rhashtable.h> |
|
#include <net/sock_reuseport.h> |
|
|
|
/* Forward declarations for internal helpers. */ |
|
static int sctp_rcv_ootb(struct sk_buff *); |
|
static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
|
struct sk_buff *skb, |
|
const union sctp_addr *paddr, |
|
const union sctp_addr *laddr, |
|
struct sctp_transport **transportp); |
|
static struct sctp_endpoint *__sctp_rcv_lookup_endpoint( |
|
struct net *net, struct sk_buff *skb, |
|
const union sctp_addr *laddr, |
|
const union sctp_addr *daddr); |
|
static struct sctp_association *__sctp_lookup_association( |
|
struct net *net, |
|
const union sctp_addr *local, |
|
const union sctp_addr *peer, |
|
struct sctp_transport **pt); |
|
|
|
static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb); |
|
|
|
|
|
/* Calculate the SCTP checksum of an SCTP packet. */ |
|
static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb) |
|
{ |
|
struct sctphdr *sh = sctp_hdr(skb); |
|
__le32 cmp = sh->checksum; |
|
__le32 val = sctp_compute_cksum(skb, 0); |
|
|
|
if (val != cmp) { |
|
/* CRC failure, dump it. */ |
|
__SCTP_INC_STATS(net, SCTP_MIB_CHECKSUMERRORS); |
|
return -1; |
|
} |
|
return 0; |
|
} |
|
|
|
/* |
|
* This is the routine which IP calls when receiving an SCTP packet. |
|
*/ |
|
int sctp_rcv(struct sk_buff *skb) |
|
{ |
|
struct sock *sk; |
|
struct sctp_association *asoc; |
|
struct sctp_endpoint *ep = NULL; |
|
struct sctp_ep_common *rcvr; |
|
struct sctp_transport *transport = NULL; |
|
struct sctp_chunk *chunk; |
|
union sctp_addr src; |
|
union sctp_addr dest; |
|
int family; |
|
struct sctp_af *af; |
|
struct net *net = dev_net(skb->dev); |
|
bool is_gso = skb_is_gso(skb) && skb_is_gso_sctp(skb); |
|
|
|
if (skb->pkt_type != PACKET_HOST) |
|
goto discard_it; |
|
|
|
__SCTP_INC_STATS(net, SCTP_MIB_INSCTPPACKS); |
|
|
|
/* If packet is too small to contain a single chunk, let's not |
|
* waste time on it anymore. |
|
*/ |
|
if (skb->len < sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) + |
|
skb_transport_offset(skb)) |
|
goto discard_it; |
|
|
|
/* If the packet is fragmented and we need to do crc checking, |
|
* it's better to just linearize it otherwise crc computing |
|
* takes longer. |
|
*/ |
|
if ((!is_gso && skb_linearize(skb)) || |
|
!pskb_may_pull(skb, sizeof(struct sctphdr))) |
|
goto discard_it; |
|
|
|
/* Pull up the IP header. */ |
|
__skb_pull(skb, skb_transport_offset(skb)); |
|
|
|
skb->csum_valid = 0; /* Previous value not applicable */ |
|
if (skb_csum_unnecessary(skb)) |
|
__skb_decr_checksum_unnecessary(skb); |
|
else if (!sctp_checksum_disable && |
|
!is_gso && |
|
sctp_rcv_checksum(net, skb) < 0) |
|
goto discard_it; |
|
skb->csum_valid = 1; |
|
|
|
__skb_pull(skb, sizeof(struct sctphdr)); |
|
|
|
family = ipver2af(ip_hdr(skb)->version); |
|
af = sctp_get_af_specific(family); |
|
if (unlikely(!af)) |
|
goto discard_it; |
|
SCTP_INPUT_CB(skb)->af = af; |
|
|
|
/* Initialize local addresses for lookups. */ |
|
af->from_skb(&src, skb, 1); |
|
af->from_skb(&dest, skb, 0); |
|
|
|
/* If the packet is to or from a non-unicast address, |
|
* silently discard the packet. |
|
* |
|
* This is not clearly defined in the RFC except in section |
|
* 8.4 - OOTB handling. However, based on the book "Stream Control |
|
* Transmission Protocol" 2.1, "It is important to note that the |
|
* IP address of an SCTP transport address must be a routable |
|
* unicast address. In other words, IP multicast addresses and |
|
* IP broadcast addresses cannot be used in an SCTP transport |
|
* address." |
|
*/ |
|
if (!af->addr_valid(&src, NULL, skb) || |
|
!af->addr_valid(&dest, NULL, skb)) |
|
goto discard_it; |
|
|
|
asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport); |
|
|
|
if (!asoc) |
|
ep = __sctp_rcv_lookup_endpoint(net, skb, &dest, &src); |
|
|
|
/* Retrieve the common input handling substructure. */ |
|
rcvr = asoc ? &asoc->base : &ep->base; |
|
sk = rcvr->sk; |
|
|
|
/* |
|
* If a frame arrives on an interface and the receiving socket is |
|
* bound to another interface, via SO_BINDTODEVICE, treat it as OOTB |
|
*/ |
|
if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) { |
|
if (transport) { |
|
sctp_transport_put(transport); |
|
asoc = NULL; |
|
transport = NULL; |
|
} else { |
|
sctp_endpoint_put(ep); |
|
ep = NULL; |
|
} |
|
sk = net->sctp.ctl_sock; |
|
ep = sctp_sk(sk)->ep; |
|
sctp_endpoint_hold(ep); |
|
rcvr = &ep->base; |
|
} |
|
|
|
/* |
|
* RFC 2960, 8.4 - Handle "Out of the blue" Packets. |
|
* An SCTP packet is called an "out of the blue" (OOTB) |
|
* packet if it is correctly formed, i.e., passed the |
|
* receiver's checksum check, but the receiver is not |
|
* able to identify the association to which this |
|
* packet belongs. |
|
*/ |
|
if (!asoc) { |
|
if (sctp_rcv_ootb(skb)) { |
|
__SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); |
|
goto discard_release; |
|
} |
|
} |
|
|
|
if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) |
|
goto discard_release; |
|
nf_reset_ct(skb); |
|
|
|
if (sk_filter(sk, skb)) |
|
goto discard_release; |
|
|
|
/* Create an SCTP packet structure. */ |
|
chunk = sctp_chunkify(skb, asoc, sk, GFP_ATOMIC); |
|
if (!chunk) |
|
goto discard_release; |
|
SCTP_INPUT_CB(skb)->chunk = chunk; |
|
|
|
/* Remember what endpoint is to handle this packet. */ |
|
chunk->rcvr = rcvr; |
|
|
|
/* Remember the SCTP header. */ |
|
chunk->sctp_hdr = sctp_hdr(skb); |
|
|
|
/* Set the source and destination addresses of the incoming chunk. */ |
|
sctp_init_addrs(chunk, &src, &dest); |
|
|
|
/* Remember where we came from. */ |
|
chunk->transport = transport; |
|
|
|
/* Acquire access to the sock lock. Note: We are safe from other |
|
* bottom halves on this lock, but a user may be in the lock too, |
|
* so check if it is busy. |
|
*/ |
|
bh_lock_sock(sk); |
|
|
|
if (sk != rcvr->sk) { |
|
/* Our cached sk is different from the rcvr->sk. This is |
|
* because migrate()/accept() may have moved the association |
|
* to a new socket and released all the sockets. So now we |
|
* are holding a lock on the old socket while the user may |
|
* be doing something with the new socket. Switch our veiw |
|
* of the current sk. |
|
*/ |
|
bh_unlock_sock(sk); |
|
sk = rcvr->sk; |
|
bh_lock_sock(sk); |
|
} |
|
|
|
if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) { |
|
if (sctp_add_backlog(sk, skb)) { |
|
bh_unlock_sock(sk); |
|
sctp_chunk_free(chunk); |
|
skb = NULL; /* sctp_chunk_free already freed the skb */ |
|
goto discard_release; |
|
} |
|
__SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_BACKLOG); |
|
} else { |
|
__SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_SOFTIRQ); |
|
sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
|
} |
|
|
|
bh_unlock_sock(sk); |
|
|
|
/* Release the asoc/ep ref we took in the lookup calls. */ |
|
if (transport) |
|
sctp_transport_put(transport); |
|
else |
|
sctp_endpoint_put(ep); |
|
|
|
return 0; |
|
|
|
discard_it: |
|
__SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); |
|
kfree_skb(skb); |
|
return 0; |
|
|
|
discard_release: |
|
/* Release the asoc/ep ref we took in the lookup calls. */ |
|
if (transport) |
|
sctp_transport_put(transport); |
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else |
|
sctp_endpoint_put(ep); |
|
|
|
goto discard_it; |
|
} |
|
|
|
/* Process the backlog queue of the socket. Every skb on |
|
* the backlog holds a ref on an association or endpoint. |
|
* We hold this ref throughout the state machine to make |
|
* sure that the structure we need is still around. |
|
*/ |
|
int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
|
struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
|
struct sctp_transport *t = chunk->transport; |
|
struct sctp_ep_common *rcvr = NULL; |
|
int backloged = 0; |
|
|
|
rcvr = chunk->rcvr; |
|
|
|
/* If the rcvr is dead then the association or endpoint |
|
* has been deleted and we can safely drop the chunk |
|
* and refs that we are holding. |
|
*/ |
|
if (rcvr->dead) { |
|
sctp_chunk_free(chunk); |
|
goto done; |
|
} |
|
|
|
if (unlikely(rcvr->sk != sk)) { |
|
/* In this case, the association moved from one socket to |
|
* another. We are currently sitting on the backlog of the |
|
* old socket, so we need to move. |
|
* However, since we are here in the process context we |
|
* need to take make sure that the user doesn't own |
|
* the new socket when we process the packet. |
|
* If the new socket is user-owned, queue the chunk to the |
|
* backlog of the new socket without dropping any refs. |
|
* Otherwise, we can safely push the chunk on the inqueue. |
|
*/ |
|
|
|
sk = rcvr->sk; |
|
local_bh_disable(); |
|
bh_lock_sock(sk); |
|
|
|
if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) { |
|
if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) |
|
sctp_chunk_free(chunk); |
|
else |
|
backloged = 1; |
|
} else |
|
sctp_inq_push(inqueue, chunk); |
|
|
|
bh_unlock_sock(sk); |
|
local_bh_enable(); |
|
|
|
/* If the chunk was backloged again, don't drop refs */ |
|
if (backloged) |
|
return 0; |
|
} else { |
|
if (!sctp_newsk_ready(sk)) { |
|
if (!sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) |
|
return 0; |
|
sctp_chunk_free(chunk); |
|
} else { |
|
sctp_inq_push(inqueue, chunk); |
|
} |
|
} |
|
|
|
done: |
|
/* Release the refs we took in sctp_add_backlog */ |
|
if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) |
|
sctp_transport_put(t); |
|
else if (SCTP_EP_TYPE_SOCKET == rcvr->type) |
|
sctp_endpoint_put(sctp_ep(rcvr)); |
|
else |
|
BUG(); |
|
|
|
return 0; |
|
} |
|
|
|
static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
|
struct sctp_transport *t = chunk->transport; |
|
struct sctp_ep_common *rcvr = chunk->rcvr; |
|
int ret; |
|
|
|
ret = sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)); |
|
if (!ret) { |
|
/* Hold the assoc/ep while hanging on the backlog queue. |
|
* This way, we know structures we need will not disappear |
|
* from us |
|
*/ |
|
if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) |
|
sctp_transport_hold(t); |
|
else if (SCTP_EP_TYPE_SOCKET == rcvr->type) |
|
sctp_endpoint_hold(sctp_ep(rcvr)); |
|
else |
|
BUG(); |
|
} |
|
return ret; |
|
|
|
} |
|
|
|
/* Handle icmp frag needed error. */ |
|
void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, |
|
struct sctp_transport *t, __u32 pmtu) |
|
{ |
|
if (!t || |
|
(t->pathmtu <= pmtu && |
|
t->pl.probe_size + sctp_transport_pl_hlen(t) <= pmtu)) |
|
return; |
|
|
|
if (sock_owned_by_user(sk)) { |
|
atomic_set(&t->mtu_info, pmtu); |
|
asoc->pmtu_pending = 1; |
|
t->pmtu_pending = 1; |
|
return; |
|
} |
|
|
|
if (!(t->param_flags & SPP_PMTUD_ENABLE)) |
|
/* We can't allow retransmitting in such case, as the |
|
* retransmission would be sized just as before, and thus we |
|
* would get another icmp, and retransmit again. |
|
*/ |
|
return; |
|
|
|
/* Update transports view of the MTU. Return if no update was needed. |
|
* If an update wasn't needed/possible, it also doesn't make sense to |
|
* try to retransmit now. |
|
*/ |
|
if (!sctp_transport_update_pmtu(t, pmtu)) |
|
return; |
|
|
|
/* Update association pmtu. */ |
|
sctp_assoc_sync_pmtu(asoc); |
|
|
|
/* Retransmit with the new pmtu setting. */ |
|
sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); |
|
} |
|
|
|
void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, |
|
struct sk_buff *skb) |
|
{ |
|
struct dst_entry *dst; |
|
|
|
if (sock_owned_by_user(sk) || !t) |
|
return; |
|
dst = sctp_transport_dst_check(t); |
|
if (dst) |
|
dst->ops->redirect(dst, sk, skb); |
|
} |
|
|
|
/* |
|
* SCTP Implementer's Guide, 2.37 ICMP handling procedures |
|
* |
|
* ICMP8) If the ICMP code is a "Unrecognized next header type encountered" |
|
* or a "Protocol Unreachable" treat this message as an abort |
|
* with the T bit set. |
|
* |
|
* This function sends an event to the state machine, which will abort the |
|
* association. |
|
* |
|
*/ |
|
void sctp_icmp_proto_unreachable(struct sock *sk, |
|
struct sctp_association *asoc, |
|
struct sctp_transport *t) |
|
{ |
|
if (sock_owned_by_user(sk)) { |
|
if (timer_pending(&t->proto_unreach_timer)) |
|
return; |
|
else { |
|
if (!mod_timer(&t->proto_unreach_timer, |
|
jiffies + (HZ/20))) |
|
sctp_transport_hold(t); |
|
} |
|
} else { |
|
struct net *net = sock_net(sk); |
|
|
|
pr_debug("%s: unrecognized next header type " |
|
"encountered!\n", __func__); |
|
|
|
if (del_timer(&t->proto_unreach_timer)) |
|
sctp_transport_put(t); |
|
|
|
sctp_do_sm(net, SCTP_EVENT_T_OTHER, |
|
SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), |
|
asoc->state, asoc->ep, asoc, t, |
|
GFP_ATOMIC); |
|
} |
|
} |
|
|
|
/* Common lookup code for icmp/icmpv6 error handler. */ |
|
struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb, |
|
struct sctphdr *sctphdr, |
|
struct sctp_association **app, |
|
struct sctp_transport **tpp) |
|
{ |
|
struct sctp_init_chunk *chunkhdr, _chunkhdr; |
|
union sctp_addr saddr; |
|
union sctp_addr daddr; |
|
struct sctp_af *af; |
|
struct sock *sk = NULL; |
|
struct sctp_association *asoc; |
|
struct sctp_transport *transport = NULL; |
|
__u32 vtag = ntohl(sctphdr->vtag); |
|
|
|
*app = NULL; *tpp = NULL; |
|
|
|
af = sctp_get_af_specific(family); |
|
if (unlikely(!af)) { |
|
return NULL; |
|
} |
|
|
|
/* Initialize local addresses for lookups. */ |
|
af->from_skb(&saddr, skb, 1); |
|
af->from_skb(&daddr, skb, 0); |
|
|
|
/* Look for an association that matches the incoming ICMP error |
|
* packet. |
|
*/ |
|
asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport); |
|
if (!asoc) |
|
return NULL; |
|
|
|
sk = asoc->base.sk; |
|
|
|
/* RFC 4960, Appendix C. ICMP Handling |
|
* |
|
* ICMP6) An implementation MUST validate that the Verification Tag |
|
* contained in the ICMP message matches the Verification Tag of |
|
* the peer. If the Verification Tag is not 0 and does NOT |
|
* match, discard the ICMP message. If it is 0 and the ICMP |
|
* message contains enough bytes to verify that the chunk type is |
|
* an INIT chunk and that the Initiate Tag matches the tag of the |
|
* peer, continue with ICMP7. If the ICMP message is too short |
|
* or the chunk type or the Initiate Tag does not match, silently |
|
* discard the packet. |
|
*/ |
|
if (vtag == 0) { |
|
/* chunk header + first 4 octects of init header */ |
|
chunkhdr = skb_header_pointer(skb, skb_transport_offset(skb) + |
|
sizeof(struct sctphdr), |
|
sizeof(struct sctp_chunkhdr) + |
|
sizeof(__be32), &_chunkhdr); |
|
if (!chunkhdr || |
|
chunkhdr->chunk_hdr.type != SCTP_CID_INIT || |
|
ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) |
|
goto out; |
|
|
|
} else if (vtag != asoc->c.peer_vtag) { |
|
goto out; |
|
} |
|
|
|
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(net, LINUX_MIB_LOCKDROPPEDICMPS); |
|
|
|
*app = asoc; |
|
*tpp = transport; |
|
return sk; |
|
|
|
out: |
|
sctp_transport_put(transport); |
|
return NULL; |
|
} |
|
|
|
/* Common cleanup code for icmp/icmpv6 error handler. */ |
|
void sctp_err_finish(struct sock *sk, struct sctp_transport *t) |
|
__releases(&((__sk)->sk_lock.slock)) |
|
{ |
|
bh_unlock_sock(sk); |
|
sctp_transport_put(t); |
|
} |
|
|
|
static void sctp_v4_err_handle(struct sctp_transport *t, struct sk_buff *skb, |
|
__u8 type, __u8 code, __u32 info) |
|
{ |
|
struct sctp_association *asoc = t->asoc; |
|
struct sock *sk = asoc->base.sk; |
|
int err = 0; |
|
|
|
switch (type) { |
|
case ICMP_PARAMETERPROB: |
|
err = EPROTO; |
|
break; |
|
case ICMP_DEST_UNREACH: |
|
if (code > NR_ICMP_UNREACH) |
|
return; |
|
if (code == ICMP_FRAG_NEEDED) { |
|
sctp_icmp_frag_needed(sk, asoc, t, SCTP_TRUNC4(info)); |
|
return; |
|
} |
|
if (code == ICMP_PROT_UNREACH) { |
|
sctp_icmp_proto_unreachable(sk, asoc, t); |
|
return; |
|
} |
|
err = icmp_err_convert[code].errno; |
|
break; |
|
case ICMP_TIME_EXCEEDED: |
|
if (code == ICMP_EXC_FRAGTIME) |
|
return; |
|
|
|
err = EHOSTUNREACH; |
|
break; |
|
case ICMP_REDIRECT: |
|
sctp_icmp_redirect(sk, t, skb); |
|
return; |
|
default: |
|
return; |
|
} |
|
if (!sock_owned_by_user(sk) && inet_sk(sk)->recverr) { |
|
sk->sk_err = err; |
|
sk_error_report(sk); |
|
} else { /* Only an error on timeout */ |
|
sk->sk_err_soft = 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 sctp 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. |
|
* |
|
*/ |
|
int sctp_v4_err(struct sk_buff *skb, __u32 info) |
|
{ |
|
const struct iphdr *iph = (const struct iphdr *)skb->data; |
|
const int type = icmp_hdr(skb)->type; |
|
const int code = icmp_hdr(skb)->code; |
|
struct net *net = dev_net(skb->dev); |
|
struct sctp_transport *transport; |
|
struct sctp_association *asoc; |
|
__u16 saveip, savesctp; |
|
struct sock *sk; |
|
|
|
/* Fix up skb to look at the embedded net header. */ |
|
saveip = skb->network_header; |
|
savesctp = skb->transport_header; |
|
skb_reset_network_header(skb); |
|
skb_set_transport_header(skb, iph->ihl * 4); |
|
sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport); |
|
/* Put back, the original values. */ |
|
skb->network_header = saveip; |
|
skb->transport_header = savesctp; |
|
if (!sk) { |
|
__ICMP_INC_STATS(net, ICMP_MIB_INERRORS); |
|
return -ENOENT; |
|
} |
|
|
|
sctp_v4_err_handle(transport, skb, type, code, info); |
|
sctp_err_finish(sk, transport); |
|
|
|
return 0; |
|
} |
|
|
|
int sctp_udp_v4_err(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
struct net *net = dev_net(skb->dev); |
|
struct sctp_association *asoc; |
|
struct sctp_transport *t; |
|
struct icmphdr *hdr; |
|
__u32 info = 0; |
|
|
|
skb->transport_header += sizeof(struct udphdr); |
|
sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &t); |
|
if (!sk) { |
|
__ICMP_INC_STATS(net, ICMP_MIB_INERRORS); |
|
return -ENOENT; |
|
} |
|
|
|
skb->transport_header -= sizeof(struct udphdr); |
|
hdr = (struct icmphdr *)(skb_network_header(skb) - sizeof(struct icmphdr)); |
|
if (hdr->type == ICMP_REDIRECT) { |
|
/* can't be handled without outer iphdr known, leave it to udp_err */ |
|
sctp_err_finish(sk, t); |
|
return 0; |
|
} |
|
if (hdr->type == ICMP_DEST_UNREACH && hdr->code == ICMP_FRAG_NEEDED) |
|
info = ntohs(hdr->un.frag.mtu); |
|
sctp_v4_err_handle(t, skb, hdr->type, hdr->code, info); |
|
|
|
sctp_err_finish(sk, t); |
|
return 1; |
|
} |
|
|
|
/* |
|
* RFC 2960, 8.4 - Handle "Out of the blue" Packets. |
|
* |
|
* This function scans all the chunks in the OOTB packet to determine if |
|
* the packet should be discarded right away. If a response might be needed |
|
* for this packet, or, if further processing is possible, the packet will |
|
* be queued to a proper inqueue for the next phase of handling. |
|
* |
|
* Output: |
|
* Return 0 - If further processing is needed. |
|
* Return 1 - If the packet can be discarded right away. |
|
*/ |
|
static int sctp_rcv_ootb(struct sk_buff *skb) |
|
{ |
|
struct sctp_chunkhdr *ch, _ch; |
|
int ch_end, offset = 0; |
|
|
|
/* Scan through all the chunks in the packet. */ |
|
do { |
|
/* Make sure we have at least the header there */ |
|
if (offset + sizeof(_ch) > skb->len) |
|
break; |
|
|
|
ch = skb_header_pointer(skb, offset, sizeof(*ch), &_ch); |
|
|
|
/* Break out if chunk length is less then minimal. */ |
|
if (!ch || ntohs(ch->length) < sizeof(_ch)) |
|
break; |
|
|
|
ch_end = offset + SCTP_PAD4(ntohs(ch->length)); |
|
if (ch_end > skb->len) |
|
break; |
|
|
|
/* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the |
|
* receiver MUST silently discard the OOTB packet and take no |
|
* further action. |
|
*/ |
|
if (SCTP_CID_ABORT == ch->type) |
|
goto discard; |
|
|
|
/* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE |
|
* chunk, the receiver should silently discard the packet |
|
* and take no further action. |
|
*/ |
|
if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) |
|
goto discard; |
|
|
|
/* RFC 4460, 2.11.2 |
|
* This will discard packets with INIT chunk bundled as |
|
* subsequent chunks in the packet. When INIT is first, |
|
* the normal INIT processing will discard the chunk. |
|
*/ |
|
if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data) |
|
goto discard; |
|
|
|
offset = ch_end; |
|
} while (ch_end < skb->len); |
|
|
|
return 0; |
|
|
|
discard: |
|
return 1; |
|
} |
|
|
|
/* Insert endpoint into the hash table. */ |
|
static int __sctp_hash_endpoint(struct sctp_endpoint *ep) |
|
{ |
|
struct sock *sk = ep->base.sk; |
|
struct net *net = sock_net(sk); |
|
struct sctp_hashbucket *head; |
|
|
|
ep->hashent = sctp_ep_hashfn(net, ep->base.bind_addr.port); |
|
head = &sctp_ep_hashtable[ep->hashent]; |
|
|
|
if (sk->sk_reuseport) { |
|
bool any = sctp_is_ep_boundall(sk); |
|
struct sctp_endpoint *ep2; |
|
struct list_head *list; |
|
int cnt = 0, err = 1; |
|
|
|
list_for_each(list, &ep->base.bind_addr.address_list) |
|
cnt++; |
|
|
|
sctp_for_each_hentry(ep2, &head->chain) { |
|
struct sock *sk2 = ep2->base.sk; |
|
|
|
if (!net_eq(sock_net(sk2), net) || sk2 == sk || |
|
!uid_eq(sock_i_uid(sk2), sock_i_uid(sk)) || |
|
!sk2->sk_reuseport) |
|
continue; |
|
|
|
err = sctp_bind_addrs_check(sctp_sk(sk2), |
|
sctp_sk(sk), cnt); |
|
if (!err) { |
|
err = reuseport_add_sock(sk, sk2, any); |
|
if (err) |
|
return err; |
|
break; |
|
} else if (err < 0) { |
|
return err; |
|
} |
|
} |
|
|
|
if (err) { |
|
err = reuseport_alloc(sk, any); |
|
if (err) |
|
return err; |
|
} |
|
} |
|
|
|
write_lock(&head->lock); |
|
hlist_add_head(&ep->node, &head->chain); |
|
write_unlock(&head->lock); |
|
return 0; |
|
} |
|
|
|
/* Add an endpoint to the hash. Local BH-safe. */ |
|
int sctp_hash_endpoint(struct sctp_endpoint *ep) |
|
{ |
|
int err; |
|
|
|
local_bh_disable(); |
|
err = __sctp_hash_endpoint(ep); |
|
local_bh_enable(); |
|
|
|
return err; |
|
} |
|
|
|
/* Remove endpoint from the hash table. */ |
|
static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) |
|
{ |
|
struct sock *sk = ep->base.sk; |
|
struct sctp_hashbucket *head; |
|
|
|
ep->hashent = sctp_ep_hashfn(sock_net(sk), ep->base.bind_addr.port); |
|
|
|
head = &sctp_ep_hashtable[ep->hashent]; |
|
|
|
if (rcu_access_pointer(sk->sk_reuseport_cb)) |
|
reuseport_detach_sock(sk); |
|
|
|
write_lock(&head->lock); |
|
hlist_del_init(&ep->node); |
|
write_unlock(&head->lock); |
|
} |
|
|
|
/* Remove endpoint from the hash. Local BH-safe. */ |
|
void sctp_unhash_endpoint(struct sctp_endpoint *ep) |
|
{ |
|
local_bh_disable(); |
|
__sctp_unhash_endpoint(ep); |
|
local_bh_enable(); |
|
} |
|
|
|
static inline __u32 sctp_hashfn(const struct net *net, __be16 lport, |
|
const union sctp_addr *paddr, __u32 seed) |
|
{ |
|
__u32 addr; |
|
|
|
if (paddr->sa.sa_family == AF_INET6) |
|
addr = jhash(&paddr->v6.sin6_addr, 16, seed); |
|
else |
|
addr = (__force __u32)paddr->v4.sin_addr.s_addr; |
|
|
|
return jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 | |
|
(__force __u32)lport, net_hash_mix(net), seed); |
|
} |
|
|
|
/* Look up an endpoint. */ |
|
static struct sctp_endpoint *__sctp_rcv_lookup_endpoint( |
|
struct net *net, struct sk_buff *skb, |
|
const union sctp_addr *laddr, |
|
const union sctp_addr *paddr) |
|
{ |
|
struct sctp_hashbucket *head; |
|
struct sctp_endpoint *ep; |
|
struct sock *sk; |
|
__be16 lport; |
|
int hash; |
|
|
|
lport = laddr->v4.sin_port; |
|
hash = sctp_ep_hashfn(net, ntohs(lport)); |
|
head = &sctp_ep_hashtable[hash]; |
|
read_lock(&head->lock); |
|
sctp_for_each_hentry(ep, &head->chain) { |
|
if (sctp_endpoint_is_match(ep, net, laddr)) |
|
goto hit; |
|
} |
|
|
|
ep = sctp_sk(net->sctp.ctl_sock)->ep; |
|
|
|
hit: |
|
sk = ep->base.sk; |
|
if (sk->sk_reuseport) { |
|
__u32 phash = sctp_hashfn(net, lport, paddr, 0); |
|
|
|
sk = reuseport_select_sock(sk, phash, skb, |
|
sizeof(struct sctphdr)); |
|
if (sk) |
|
ep = sctp_sk(sk)->ep; |
|
} |
|
sctp_endpoint_hold(ep); |
|
read_unlock(&head->lock); |
|
return ep; |
|
} |
|
|
|
/* rhashtable for transport */ |
|
struct sctp_hash_cmp_arg { |
|
const union sctp_addr *paddr; |
|
const struct net *net; |
|
__be16 lport; |
|
}; |
|
|
|
static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg, |
|
const void *ptr) |
|
{ |
|
struct sctp_transport *t = (struct sctp_transport *)ptr; |
|
const struct sctp_hash_cmp_arg *x = arg->key; |
|
int err = 1; |
|
|
|
if (!sctp_cmp_addr_exact(&t->ipaddr, x->paddr)) |
|
return err; |
|
if (!sctp_transport_hold(t)) |
|
return err; |
|
|
|
if (!net_eq(t->asoc->base.net, x->net)) |
|
goto out; |
|
if (x->lport != htons(t->asoc->base.bind_addr.port)) |
|
goto out; |
|
|
|
err = 0; |
|
out: |
|
sctp_transport_put(t); |
|
return err; |
|
} |
|
|
|
static inline __u32 sctp_hash_obj(const void *data, u32 len, u32 seed) |
|
{ |
|
const struct sctp_transport *t = data; |
|
|
|
return sctp_hashfn(t->asoc->base.net, |
|
htons(t->asoc->base.bind_addr.port), |
|
&t->ipaddr, seed); |
|
} |
|
|
|
static inline __u32 sctp_hash_key(const void *data, u32 len, u32 seed) |
|
{ |
|
const struct sctp_hash_cmp_arg *x = data; |
|
|
|
return sctp_hashfn(x->net, x->lport, x->paddr, seed); |
|
} |
|
|
|
static const struct rhashtable_params sctp_hash_params = { |
|
.head_offset = offsetof(struct sctp_transport, node), |
|
.hashfn = sctp_hash_key, |
|
.obj_hashfn = sctp_hash_obj, |
|
.obj_cmpfn = sctp_hash_cmp, |
|
.automatic_shrinking = true, |
|
}; |
|
|
|
int sctp_transport_hashtable_init(void) |
|
{ |
|
return rhltable_init(&sctp_transport_hashtable, &sctp_hash_params); |
|
} |
|
|
|
void sctp_transport_hashtable_destroy(void) |
|
{ |
|
rhltable_destroy(&sctp_transport_hashtable); |
|
} |
|
|
|
int sctp_hash_transport(struct sctp_transport *t) |
|
{ |
|
struct sctp_transport *transport; |
|
struct rhlist_head *tmp, *list; |
|
struct sctp_hash_cmp_arg arg; |
|
int err; |
|
|
|
if (t->asoc->temp) |
|
return 0; |
|
|
|
arg.net = t->asoc->base.net; |
|
arg.paddr = &t->ipaddr; |
|
arg.lport = htons(t->asoc->base.bind_addr.port); |
|
|
|
rcu_read_lock(); |
|
list = rhltable_lookup(&sctp_transport_hashtable, &arg, |
|
sctp_hash_params); |
|
|
|
rhl_for_each_entry_rcu(transport, tmp, list, node) |
|
if (transport->asoc->ep == t->asoc->ep) { |
|
rcu_read_unlock(); |
|
return -EEXIST; |
|
} |
|
rcu_read_unlock(); |
|
|
|
err = rhltable_insert_key(&sctp_transport_hashtable, &arg, |
|
&t->node, sctp_hash_params); |
|
if (err) |
|
pr_err_once("insert transport fail, errno %d\n", err); |
|
|
|
return err; |
|
} |
|
|
|
void sctp_unhash_transport(struct sctp_transport *t) |
|
{ |
|
if (t->asoc->temp) |
|
return; |
|
|
|
rhltable_remove(&sctp_transport_hashtable, &t->node, |
|
sctp_hash_params); |
|
} |
|
|
|
/* return a transport with holding it */ |
|
struct sctp_transport *sctp_addrs_lookup_transport( |
|
struct net *net, |
|
const union sctp_addr *laddr, |
|
const union sctp_addr *paddr) |
|
{ |
|
struct rhlist_head *tmp, *list; |
|
struct sctp_transport *t; |
|
struct sctp_hash_cmp_arg arg = { |
|
.paddr = paddr, |
|
.net = net, |
|
.lport = laddr->v4.sin_port, |
|
}; |
|
|
|
list = rhltable_lookup(&sctp_transport_hashtable, &arg, |
|
sctp_hash_params); |
|
|
|
rhl_for_each_entry_rcu(t, tmp, list, node) { |
|
if (!sctp_transport_hold(t)) |
|
continue; |
|
|
|
if (sctp_bind_addr_match(&t->asoc->base.bind_addr, |
|
laddr, sctp_sk(t->asoc->base.sk))) |
|
return t; |
|
sctp_transport_put(t); |
|
} |
|
|
|
return NULL; |
|
} |
|
|
|
/* return a transport without holding it, as it's only used under sock lock */ |
|
struct sctp_transport *sctp_epaddr_lookup_transport( |
|
const struct sctp_endpoint *ep, |
|
const union sctp_addr *paddr) |
|
{ |
|
struct rhlist_head *tmp, *list; |
|
struct sctp_transport *t; |
|
struct sctp_hash_cmp_arg arg = { |
|
.paddr = paddr, |
|
.net = ep->base.net, |
|
.lport = htons(ep->base.bind_addr.port), |
|
}; |
|
|
|
list = rhltable_lookup(&sctp_transport_hashtable, &arg, |
|
sctp_hash_params); |
|
|
|
rhl_for_each_entry_rcu(t, tmp, list, node) |
|
if (ep == t->asoc->ep) |
|
return t; |
|
|
|
return NULL; |
|
} |
|
|
|
/* Look up an association. */ |
|
static struct sctp_association *__sctp_lookup_association( |
|
struct net *net, |
|
const union sctp_addr *local, |
|
const union sctp_addr *peer, |
|
struct sctp_transport **pt) |
|
{ |
|
struct sctp_transport *t; |
|
struct sctp_association *asoc = NULL; |
|
|
|
t = sctp_addrs_lookup_transport(net, local, peer); |
|
if (!t) |
|
goto out; |
|
|
|
asoc = t->asoc; |
|
*pt = t; |
|
|
|
out: |
|
return asoc; |
|
} |
|
|
|
/* Look up an association. protected by RCU read lock */ |
|
static |
|
struct sctp_association *sctp_lookup_association(struct net *net, |
|
const union sctp_addr *laddr, |
|
const union sctp_addr *paddr, |
|
struct sctp_transport **transportp) |
|
{ |
|
struct sctp_association *asoc; |
|
|
|
rcu_read_lock(); |
|
asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
|
rcu_read_unlock(); |
|
|
|
return asoc; |
|
} |
|
|
|
/* Is there an association matching the given local and peer addresses? */ |
|
bool sctp_has_association(struct net *net, |
|
const union sctp_addr *laddr, |
|
const union sctp_addr *paddr) |
|
{ |
|
struct sctp_transport *transport; |
|
|
|
if (sctp_lookup_association(net, laddr, paddr, &transport)) { |
|
sctp_transport_put(transport); |
|
return true; |
|
} |
|
|
|
return false; |
|
} |
|
|
|
/* |
|
* SCTP Implementors Guide, 2.18 Handling of address |
|
* parameters within the INIT or INIT-ACK. |
|
* |
|
* D) When searching for a matching TCB upon reception of an INIT |
|
* or INIT-ACK chunk the receiver SHOULD use not only the |
|
* source address of the packet (containing the INIT or |
|
* INIT-ACK) but the receiver SHOULD also use all valid |
|
* address parameters contained within the chunk. |
|
* |
|
* 2.18.3 Solution description |
|
* |
|
* This new text clearly specifies to an implementor the need |
|
* to look within the INIT or INIT-ACK. Any implementation that |
|
* does not do this, may not be able to establish associations |
|
* in certain circumstances. |
|
* |
|
*/ |
|
static struct sctp_association *__sctp_rcv_init_lookup(struct net *net, |
|
struct sk_buff *skb, |
|
const union sctp_addr *laddr, struct sctp_transport **transportp) |
|
{ |
|
struct sctp_association *asoc; |
|
union sctp_addr addr; |
|
union sctp_addr *paddr = &addr; |
|
struct sctphdr *sh = sctp_hdr(skb); |
|
union sctp_params params; |
|
struct sctp_init_chunk *init; |
|
struct sctp_af *af; |
|
|
|
/* |
|
* This code will NOT touch anything inside the chunk--it is |
|
* strictly READ-ONLY. |
|
* |
|
* RFC 2960 3 SCTP packet Format |
|
* |
|
* Multiple chunks can be bundled into one SCTP packet up to |
|
* the MTU size, except for the INIT, INIT ACK, and SHUTDOWN |
|
* COMPLETE chunks. These chunks MUST NOT be bundled with any |
|
* other chunk in a packet. See Section 6.10 for more details |
|
* on chunk bundling. |
|
*/ |
|
|
|
/* Find the start of the TLVs and the end of the chunk. This is |
|
* the region we search for address parameters. |
|
*/ |
|
init = (struct sctp_init_chunk *)skb->data; |
|
|
|
/* Walk the parameters looking for embedded addresses. */ |
|
sctp_walk_params(params, init, init_hdr.params) { |
|
|
|
/* Note: Ignoring hostname addresses. */ |
|
af = sctp_get_af_specific(param_type2af(params.p->type)); |
|
if (!af) |
|
continue; |
|
|
|
if (!af->from_addr_param(paddr, params.addr, sh->source, 0)) |
|
continue; |
|
|
|
asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
|
if (asoc) |
|
return asoc; |
|
} |
|
|
|
return NULL; |
|
} |
|
|
|
/* ADD-IP, Section 5.2 |
|
* When an endpoint receives an ASCONF Chunk from the remote peer |
|
* special procedures may be needed to identify the association the |
|
* ASCONF Chunk is associated with. To properly find the association |
|
* the following procedures SHOULD be followed: |
|
* |
|
* D2) If the association is not found, use the address found in the |
|
* Address Parameter TLV combined with the port number found in the |
|
* SCTP common header. If found proceed to rule D4. |
|
* |
|
* D2-ext) If more than one ASCONF Chunks are packed together, use the |
|
* address found in the ASCONF Address Parameter TLV of each of the |
|
* subsequent ASCONF Chunks. If found, proceed to rule D4. |
|
*/ |
|
static struct sctp_association *__sctp_rcv_asconf_lookup( |
|
struct net *net, |
|
struct sctp_chunkhdr *ch, |
|
const union sctp_addr *laddr, |
|
__be16 peer_port, |
|
struct sctp_transport **transportp) |
|
{ |
|
struct sctp_addip_chunk *asconf = (struct sctp_addip_chunk *)ch; |
|
struct sctp_af *af; |
|
union sctp_addr_param *param; |
|
union sctp_addr paddr; |
|
|
|
if (ntohs(ch->length) < sizeof(*asconf) + sizeof(struct sctp_paramhdr)) |
|
return NULL; |
|
|
|
/* Skip over the ADDIP header and find the Address parameter */ |
|
param = (union sctp_addr_param *)(asconf + 1); |
|
|
|
af = sctp_get_af_specific(param_type2af(param->p.type)); |
|
if (unlikely(!af)) |
|
return NULL; |
|
|
|
if (!af->from_addr_param(&paddr, param, peer_port, 0)) |
|
return NULL; |
|
|
|
return __sctp_lookup_association(net, laddr, &paddr, transportp); |
|
} |
|
|
|
|
|
/* SCTP-AUTH, Section 6.3: |
|
* If the receiver does not find a STCB for a packet containing an AUTH |
|
* chunk as the first chunk and not a COOKIE-ECHO chunk as the second |
|
* chunk, it MUST use the chunks after the AUTH chunk to look up an existing |
|
* association. |
|
* |
|
* This means that any chunks that can help us identify the association need |
|
* to be looked at to find this association. |
|
*/ |
|
static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net, |
|
struct sk_buff *skb, |
|
const union sctp_addr *laddr, |
|
struct sctp_transport **transportp) |
|
{ |
|
struct sctp_association *asoc = NULL; |
|
struct sctp_chunkhdr *ch; |
|
int have_auth = 0; |
|
unsigned int chunk_num = 1; |
|
__u8 *ch_end; |
|
|
|
/* Walk through the chunks looking for AUTH or ASCONF chunks |
|
* to help us find the association. |
|
*/ |
|
ch = (struct sctp_chunkhdr *)skb->data; |
|
do { |
|
/* Break out if chunk length is less then minimal. */ |
|
if (ntohs(ch->length) < sizeof(*ch)) |
|
break; |
|
|
|
ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); |
|
if (ch_end > skb_tail_pointer(skb)) |
|
break; |
|
|
|
switch (ch->type) { |
|
case SCTP_CID_AUTH: |
|
have_auth = chunk_num; |
|
break; |
|
|
|
case SCTP_CID_COOKIE_ECHO: |
|
/* If a packet arrives containing an AUTH chunk as |
|
* a first chunk, a COOKIE-ECHO chunk as the second |
|
* chunk, and possibly more chunks after them, and |
|
* the receiver does not have an STCB for that |
|
* packet, then authentication is based on |
|
* the contents of the COOKIE- ECHO chunk. |
|
*/ |
|
if (have_auth == 1 && chunk_num == 2) |
|
return NULL; |
|
break; |
|
|
|
case SCTP_CID_ASCONF: |
|
if (have_auth || net->sctp.addip_noauth) |
|
asoc = __sctp_rcv_asconf_lookup( |
|
net, ch, laddr, |
|
sctp_hdr(skb)->source, |
|
transportp); |
|
break; |
|
default: |
|
break; |
|
} |
|
|
|
if (asoc) |
|
break; |
|
|
|
ch = (struct sctp_chunkhdr *)ch_end; |
|
chunk_num++; |
|
} while (ch_end + sizeof(*ch) < skb_tail_pointer(skb)); |
|
|
|
return asoc; |
|
} |
|
|
|
/* |
|
* There are circumstances when we need to look inside the SCTP packet |
|
* for information to help us find the association. Examples |
|
* include looking inside of INIT/INIT-ACK chunks or after the AUTH |
|
* chunks. |
|
*/ |
|
static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net, |
|
struct sk_buff *skb, |
|
const union sctp_addr *laddr, |
|
struct sctp_transport **transportp) |
|
{ |
|
struct sctp_chunkhdr *ch; |
|
|
|
/* We do not allow GSO frames here as we need to linearize and |
|
* then cannot guarantee frame boundaries. This shouldn't be an |
|
* issue as packets hitting this are mostly INIT or INIT-ACK and |
|
* those cannot be on GSO-style anyway. |
|
*/ |
|
if (skb_is_gso(skb) && skb_is_gso_sctp(skb)) |
|
return NULL; |
|
|
|
ch = (struct sctp_chunkhdr *)skb->data; |
|
|
|
/* The code below will attempt to walk the chunk and extract |
|
* parameter information. Before we do that, we need to verify |
|
* that the chunk length doesn't cause overflow. Otherwise, we'll |
|
* walk off the end. |
|
*/ |
|
if (SCTP_PAD4(ntohs(ch->length)) > skb->len) |
|
return NULL; |
|
|
|
/* If this is INIT/INIT-ACK look inside the chunk too. */ |
|
if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK) |
|
return __sctp_rcv_init_lookup(net, skb, laddr, transportp); |
|
|
|
return __sctp_rcv_walk_lookup(net, skb, laddr, transportp); |
|
} |
|
|
|
/* Lookup an association for an inbound skb. */ |
|
static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
|
struct sk_buff *skb, |
|
const union sctp_addr *paddr, |
|
const union sctp_addr *laddr, |
|
struct sctp_transport **transportp) |
|
{ |
|
struct sctp_association *asoc; |
|
|
|
asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
|
if (asoc) |
|
goto out; |
|
|
|
/* Further lookup for INIT/INIT-ACK packets. |
|
* SCTP Implementors Guide, 2.18 Handling of address |
|
* parameters within the INIT or INIT-ACK. |
|
*/ |
|
asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp); |
|
if (asoc) |
|
goto out; |
|
|
|
if (paddr->sa.sa_family == AF_INET) |
|
pr_debug("sctp: asoc not found for src:%pI4:%d dst:%pI4:%d\n", |
|
&laddr->v4.sin_addr, ntohs(laddr->v4.sin_port), |
|
&paddr->v4.sin_addr, ntohs(paddr->v4.sin_port)); |
|
else |
|
pr_debug("sctp: asoc not found for src:%pI6:%d dst:%pI6:%d\n", |
|
&laddr->v6.sin6_addr, ntohs(laddr->v6.sin6_port), |
|
&paddr->v6.sin6_addr, ntohs(paddr->v6.sin6_port)); |
|
|
|
out: |
|
return asoc; |
|
}
|
|
|