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authorXin Long <lucien.xin@gmail.com>2016-10-31 19:49:41 +0300
committerDavid S. Miller <davem@davemloft.net>2016-11-02 22:03:13 +0300
commite4ff952a7e11e51789949ed738c3c9455e5fd6c0 (patch)
tree89b6b808602a3c6942321a814d6292947a2ddae1 /net/sctp
parent92901827538f87bd7e1ec41a7a1c3ebe22bb78f5 (diff)
downloadlinux-e4ff952a7e11e51789949ed738c3c9455e5fd6c0.tar.xz
sctp: clean up sctp_packet_transmit
After adding sctp gso, sctp_packet_transmit is a quite big function now. This patch is to extract the codes for packing packet to sctp_packet_pack from sctp_packet_transmit, and add some comments, simplify the err path by freeing auth chunk when freeing packet chunk_list in out path and freeing head skb early if it fails to pack packet. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp')
-rw-r--r--net/sctp/output.c435
1 files changed, 158 insertions, 277 deletions
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 7b50e4307485..f5320a87341e 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -399,187 +399,72 @@ static void sctp_packet_set_owner_w(struct sk_buff *skb, struct sock *sk)
atomic_inc(&sk->sk_wmem_alloc);
}
-/* All packets are sent to the network through this function from
- * sctp_outq_tail().
- *
- * The return value is a normal kernel error return value.
- */
-int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
+static int sctp_packet_pack(struct sctp_packet *packet,
+ struct sk_buff *head, int gso, gfp_t gfp)
{
struct sctp_transport *tp = packet->transport;
- struct sctp_association *asoc = tp->asoc;
- struct sctphdr *sh;
- struct sk_buff *nskb = NULL, *head = NULL;
+ struct sctp_auth_chunk *auth = NULL;
struct sctp_chunk *chunk, *tmp;
- struct sock *sk;
- int err = 0;
- int padding; /* How much padding do we need? */
- int pkt_size;
- __u8 has_data = 0;
- int gso = 0;
- int pktcount = 0;
+ int pkt_count = 0, pkt_size;
+ struct sock *sk = head->sk;
+ struct sk_buff *nskb;
int auth_len = 0;
- struct dst_entry *dst;
- unsigned char *auth = NULL; /* pointer to auth in skb data */
-
- pr_debug("%s: packet:%p\n", __func__, packet);
- /* Do NOT generate a chunkless packet. */
- if (list_empty(&packet->chunk_list))
- return err;
-
- /* Set up convenience variables... */
- chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list);
- sk = chunk->skb->sk;
-
- /* Allocate the head skb, or main one if not in GSO */
- if (packet->size > tp->pathmtu && !packet->ipfragok) {
- if (sk_can_gso(sk)) {
- gso = 1;
- pkt_size = packet->overhead;
- } else {
- /* If this happens, we trash this packet and try
- * to build a new one, hopefully correct this
- * time. Application may notice this error.
- */
- pr_err_once("Trying to GSO but underlying device doesn't support it.");
- goto err;
- }
- } else {
- pkt_size = packet->size;
- }
- head = alloc_skb(pkt_size + MAX_HEADER, gfp);
- if (!head)
- goto err;
if (gso) {
- NAPI_GRO_CB(head)->last = head;
skb_shinfo(head)->gso_type = sk->sk_gso_type;
+ NAPI_GRO_CB(head)->last = head;
+ } else {
+ nskb = head;
+ pkt_size = packet->size;
+ goto merge;
}
- /* Make sure the outbound skb has enough header room reserved. */
- skb_reserve(head, packet->overhead + MAX_HEADER);
-
- /* Set the owning socket so that we know where to get the
- * destination IP address.
- */
- sctp_packet_set_owner_w(head, sk);
-
- if (!sctp_transport_dst_check(tp)) {
- sctp_transport_route(tp, NULL, sctp_sk(sk));
- if (asoc && (asoc->param_flags & SPP_PMTUD_ENABLE)) {
- sctp_assoc_sync_pmtu(sk, asoc);
- }
- }
- dst = dst_clone(tp->dst);
- if (!dst) {
- if (asoc)
- IP_INC_STATS(sock_net(asoc->base.sk),
- IPSTATS_MIB_OUTNOROUTES);
- goto nodst;
- }
- skb_dst_set(head, dst);
-
- /* Build the SCTP header. */
- sh = (struct sctphdr *)skb_push(head, sizeof(struct sctphdr));
- skb_reset_transport_header(head);
- sh->source = htons(packet->source_port);
- sh->dest = htons(packet->destination_port);
-
- /* From 6.8 Adler-32 Checksum Calculation:
- * After the packet is constructed (containing the SCTP common
- * header and one or more control or DATA chunks), the
- * transmitter shall:
- *
- * 1) Fill in the proper Verification Tag in the SCTP common
- * header and initialize the checksum field to 0's.
- */
- sh->vtag = htonl(packet->vtag);
- sh->checksum = 0;
-
- pr_debug("***sctp_transmit_packet***\n");
-
do {
- /* Set up convenience variables... */
- chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list);
- pktcount++;
-
- /* Calculate packet size, so it fits in PMTU. Leave
- * other chunks for the next packets.
- */
- if (gso) {
- pkt_size = packet->overhead;
- list_for_each_entry(chunk, &packet->chunk_list, list) {
- int padded = SCTP_PAD4(chunk->skb->len);
-
- if (chunk == packet->auth)
- auth_len = padded;
- else if (auth_len + padded + packet->overhead >
- tp->pathmtu)
- goto nomem;
- else if (pkt_size + padded > tp->pathmtu)
- break;
- pkt_size += padded;
- }
-
- /* Allocate a new skb. */
- nskb = alloc_skb(pkt_size + MAX_HEADER, gfp);
- if (!nskb)
- goto nomem;
+ /* calculate the pkt_size and alloc nskb */
+ pkt_size = packet->overhead;
+ list_for_each_entry_safe(chunk, tmp, &packet->chunk_list,
+ list) {
+ int padded = SCTP_PAD4(chunk->skb->len);
- /* Make sure the outbound skb has enough header
- * room reserved.
- */
- skb_reserve(nskb, packet->overhead + MAX_HEADER);
- } else {
- nskb = head;
+ if (chunk == packet->auth)
+ auth_len = padded;
+ else if (auth_len + padded + packet->overhead >
+ tp->pathmtu)
+ return 0;
+ else if (pkt_size + padded > tp->pathmtu)
+ break;
+ pkt_size += padded;
}
+ nskb = alloc_skb(pkt_size + MAX_HEADER, gfp);
+ if (!nskb)
+ return 0;
+ skb_reserve(nskb, packet->overhead + MAX_HEADER);
- /**
- * 3.2 Chunk Field Descriptions
- *
- * The total length of a chunk (including Type, Length and
- * Value fields) MUST be a multiple of 4 bytes. If the length
- * of the chunk is not a multiple of 4 bytes, the sender MUST
- * pad the chunk with all zero bytes and this padding is not
- * included in the chunk length field. The sender should
- * never pad with more than 3 bytes.
- *
- * [This whole comment explains SCTP_PAD4() below.]
- */
-
+merge:
+ /* merge chunks into nskb and append nskb into head list */
pkt_size -= packet->overhead;
list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
+ int padding;
+
list_del_init(&chunk->list);
if (sctp_chunk_is_data(chunk)) {
- /* 6.3.1 C4) When data is in flight and when allowed
- * by rule C5, a new RTT measurement MUST be made each
- * round trip. Furthermore, new RTT measurements
- * SHOULD be made no more than once per round-trip
- * for a given destination transport address.
- */
-
if (!sctp_chunk_retransmitted(chunk) &&
!tp->rto_pending) {
chunk->rtt_in_progress = 1;
tp->rto_pending = 1;
}
-
- has_data = 1;
}
padding = SCTP_PAD4(chunk->skb->len) - chunk->skb->len;
if (padding)
memset(skb_put(chunk->skb, padding), 0, padding);
- /* if this is the auth chunk that we are adding,
- * store pointer where it will be added and put
- * the auth into the packet.
- */
if (chunk == packet->auth)
- auth = skb_tail_pointer(nskb);
+ auth = (struct sctp_auth_chunk *)
+ skb_tail_pointer(nskb);
- memcpy(skb_put(nskb, chunk->skb->len),
- chunk->skb->data, chunk->skb->len);
+ memcpy(skb_put(nskb, chunk->skb->len), chunk->skb->data,
+ chunk->skb->len);
pr_debug("*** Chunk:%p[%s] %s 0x%x, length:%d, chunk->skb->len:%d, rtt_in_progress:%d\n",
chunk,
@@ -589,11 +474,6 @@ int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
ntohs(chunk->chunk_hdr->length), chunk->skb->len,
chunk->rtt_in_progress);
- /* If this is a control chunk, this is our last
- * reference. Free data chunks after they've been
- * acknowledged or have failed.
- * Re-queue auth chunks if needed.
- */
pkt_size -= SCTP_PAD4(chunk->skb->len);
if (!sctp_chunk_is_data(chunk) && chunk != packet->auth)
@@ -603,160 +483,161 @@ int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
break;
}
- /* SCTP-AUTH, Section 6.2
- * The sender MUST calculate the MAC as described in RFC2104 [2]
- * using the hash function H as described by the MAC Identifier and
- * the shared association key K based on the endpoint pair shared key
- * described by the shared key identifier. The 'data' used for the
- * computation of the AUTH-chunk is given by the AUTH chunk with its
- * HMAC field set to zero (as shown in Figure 6) followed by all
- * chunks that are placed after the AUTH chunk in the SCTP packet.
- */
- if (auth)
- sctp_auth_calculate_hmac(asoc, nskb,
- (struct sctp_auth_chunk *)auth,
- gfp);
-
- if (packet->auth) {
- if (!list_empty(&packet->chunk_list)) {
- /* We will generate more packets, so re-queue
- * auth chunk.
- */
+ if (auth) {
+ sctp_auth_calculate_hmac(tp->asoc, nskb, auth, gfp);
+ /* free auth if no more chunks, or add it back */
+ if (list_empty(&packet->chunk_list))
+ sctp_chunk_free(packet->auth);
+ else
list_add(&packet->auth->list,
&packet->chunk_list);
- } else {
- sctp_chunk_free(packet->auth);
- packet->auth = NULL;
- }
}
- if (!gso)
- break;
-
- if (skb_gro_receive(&head, nskb)) {
- kfree_skb(nskb);
- goto nomem;
+ if (gso) {
+ if (skb_gro_receive(&head, nskb)) {
+ kfree_skb(nskb);
+ return 0;
+ }
+ if (WARN_ON_ONCE(skb_shinfo(head)->gso_segs >=
+ sk->sk_gso_max_segs))
+ return 0;
}
- nskb = NULL;
- if (WARN_ON_ONCE(skb_shinfo(head)->gso_segs >=
- sk->sk_gso_max_segs))
- goto nomem;
+
+ pkt_count++;
} while (!list_empty(&packet->chunk_list));
- /* 2) Calculate the Adler-32 checksum of the whole packet,
- * including the SCTP common header and all the
- * chunks.
- *
- * Note: Adler-32 is no longer applicable, as has been replaced
- * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>.
- *
- * If it's a GSO packet, it's postponed to sctp_skb_segment.
- */
- if (!sctp_checksum_disable || gso) {
- if (!gso && (!(dst->dev->features & NETIF_F_SCTP_CRC) ||
- dst_xfrm(dst) || packet->ipfragok)) {
- sh->checksum = sctp_compute_cksum(head, 0);
- } else {
- /* no need to seed pseudo checksum for SCTP */
- head->ip_summed = CHECKSUM_PARTIAL;
- head->csum_start = skb_transport_header(head) - head->head;
- head->csum_offset = offsetof(struct sctphdr, checksum);
+ if (gso) {
+ memset(head->cb, 0, max(sizeof(struct inet_skb_parm),
+ sizeof(struct inet6_skb_parm)));
+ skb_shinfo(head)->gso_segs = pkt_count;
+ skb_shinfo(head)->gso_size = GSO_BY_FRAGS;
+ rcu_read_lock();
+ if (skb_dst(head) != tp->dst) {
+ dst_hold(tp->dst);
+ sk_setup_caps(sk, tp->dst);
}
+ rcu_read_unlock();
+ goto chksum;
}
- /* IP layer ECN support
- * From RFC 2481
- * "The ECN-Capable Transport (ECT) bit would be set by the
- * data sender to indicate that the end-points of the
- * transport protocol are ECN-capable."
- *
- * Now setting the ECT bit all the time, as it should not cause
- * any problems protocol-wise even if our peer ignores it.
- *
- * Note: The works for IPv6 layer checks this bit too later
- * in transmission. See IP6_ECN_flow_xmit().
- */
- tp->af_specific->ecn_capable(sk);
+ if (sctp_checksum_disable)
+ return 1;
- /* Set up the IP options. */
- /* BUG: not implemented
- * For v4 this all lives somewhere in sk->sk_opt...
- */
+ if (!(skb_dst(head)->dev->features & NETIF_F_SCTP_CRC) ||
+ dst_xfrm(skb_dst(head)) || packet->ipfragok) {
+ struct sctphdr *sh =
+ (struct sctphdr *)skb_transport_header(head);
- /* Dump that on IP! */
- if (asoc) {
- asoc->stats.opackets += pktcount;
- if (asoc->peer.last_sent_to != tp)
- /* Considering the multiple CPU scenario, this is a
- * "correcter" place for last_sent_to. --xguo
- */
- asoc->peer.last_sent_to = tp;
+ sh->checksum = sctp_compute_cksum(head, 0);
+ } else {
+chksum:
+ head->ip_summed = CHECKSUM_PARTIAL;
+ head->csum_start = skb_transport_header(head) - head->head;
+ head->csum_offset = offsetof(struct sctphdr, checksum);
}
- if (has_data) {
- struct timer_list *timer;
- unsigned long timeout;
+ return pkt_count;
+}
+
+/* All packets are sent to the network through this function from
+ * sctp_outq_tail().
+ *
+ * The return value is always 0 for now.
+ */
+int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp)
+{
+ struct sctp_transport *tp = packet->transport;
+ struct sctp_association *asoc = tp->asoc;
+ struct sctp_chunk *chunk, *tmp;
+ int pkt_count, gso = 0;
+ struct dst_entry *dst;
+ struct sk_buff *head;
+ struct sctphdr *sh;
+ struct sock *sk;
- /* Restart the AUTOCLOSE timer when sending data. */
- if (sctp_state(asoc, ESTABLISHED) &&
- asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
- timer = &asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
- timeout = asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
+ pr_debug("%s: packet:%p\n", __func__, packet);
+ if (list_empty(&packet->chunk_list))
+ return 0;
+ chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list);
+ sk = chunk->skb->sk;
- if (!mod_timer(timer, jiffies + timeout))
- sctp_association_hold(asoc);
+ /* check gso */
+ if (packet->size > tp->pathmtu && !packet->ipfragok) {
+ if (!sk_can_gso(sk)) {
+ pr_err_once("Trying to GSO but underlying device doesn't support it.");
+ goto out;
}
+ gso = 1;
+ }
+
+ /* alloc head skb */
+ head = alloc_skb((gso ? packet->overhead : packet->size) +
+ MAX_HEADER, gfp);
+ if (!head)
+ goto out;
+ skb_reserve(head, packet->overhead + MAX_HEADER);
+ sctp_packet_set_owner_w(head, sk);
+
+ /* set sctp header */
+ sh = (struct sctphdr *)skb_push(head, sizeof(struct sctphdr));
+ skb_reset_transport_header(head);
+ sh->source = htons(packet->source_port);
+ sh->dest = htons(packet->destination_port);
+ sh->vtag = htonl(packet->vtag);
+ sh->checksum = 0;
+
+ /* update dst if in need */
+ if (!sctp_transport_dst_check(tp)) {
+ sctp_transport_route(tp, NULL, sctp_sk(sk));
+ if (asoc && asoc->param_flags & SPP_PMTUD_ENABLE)
+ sctp_assoc_sync_pmtu(sk, asoc);
}
+ dst = dst_clone(tp->dst);
+ if (!dst) {
+ IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
+ kfree_skb(head);
+ goto out;
+ }
+ skb_dst_set(head, dst);
+ /* pack up chunks */
+ pkt_count = sctp_packet_pack(packet, head, gso, gfp);
+ if (!pkt_count) {
+ kfree_skb(head);
+ goto out;
+ }
pr_debug("***sctp_transmit_packet*** skb->len:%d\n", head->len);
- if (gso) {
- /* Cleanup our debris for IP stacks */
- memset(head->cb, 0, max(sizeof(struct inet_skb_parm),
- sizeof(struct inet6_skb_parm)));
+ /* start autoclose timer */
+ if (packet->has_data && sctp_state(asoc, ESTABLISHED) &&
+ asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
+ struct timer_list *timer =
+ &asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
+ unsigned long timeout =
+ asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
- skb_shinfo(head)->gso_segs = pktcount;
- skb_shinfo(head)->gso_size = GSO_BY_FRAGS;
+ if (!mod_timer(timer, jiffies + timeout))
+ sctp_association_hold(asoc);
+ }
- /* We have to refresh this in case we are xmiting to
- * more than one transport at a time
- */
- rcu_read_lock();
- if (__sk_dst_get(sk) != tp->dst) {
- dst_hold(tp->dst);
- sk_setup_caps(sk, tp->dst);
- }
- rcu_read_unlock();
+ /* sctp xmit */
+ tp->af_specific->ecn_capable(sk);
+ if (asoc) {
+ asoc->stats.opackets += pkt_count;
+ if (asoc->peer.last_sent_to != tp)
+ asoc->peer.last_sent_to = tp;
}
head->ignore_df = packet->ipfragok;
tp->af_specific->sctp_xmit(head, tp);
- goto out;
-
-nomem:
- if (packet->auth && list_empty(&packet->auth->list))
- sctp_chunk_free(packet->auth);
-
-nodst:
- /* FIXME: Returning the 'err' will effect all the associations
- * associated with a socket, although only one of the paths of the
- * association is unreachable.
- * The real failure of a transport or association can be passed on
- * to the user via notifications. So setting this error may not be
- * required.
- */
- /* err = -EHOSTUNREACH; */
- kfree_skb(head);
-err:
+out:
list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
list_del_init(&chunk->list);
if (!sctp_chunk_is_data(chunk))
sctp_chunk_free(chunk);
}
-
-out:
sctp_packet_reset(packet);
- return err;
+ return 0;
}
/********************************************************************