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-rw-r--r--net/sctp/chunk.c353
1 files changed, 353 insertions, 0 deletions
diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
new file mode 100644
index 000000000..fd4f8243c
--- /dev/null
+++ b/net/sctp/chunk.c
@@ -0,0 +1,353 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* SCTP kernel implementation
+ * (C) Copyright IBM Corp. 2003, 2004
+ *
+ * This file is part of the SCTP kernel implementation
+ *
+ * This file contains the code relating the chunk abstraction.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email address(es):
+ * lksctp developers <linux-sctp@vger.kernel.org>
+ *
+ * Written or modified by:
+ * Jon Grimm <jgrimm@us.ibm.com>
+ * Sridhar Samudrala <sri@us.ibm.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/net.h>
+#include <linux/inet.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <net/sock.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+
+/* This file is mostly in anticipation of future work, but initially
+ * populate with fragment tracking for an outbound message.
+ */
+
+/* Initialize datamsg from memory. */
+static void sctp_datamsg_init(struct sctp_datamsg *msg)
+{
+ refcount_set(&msg->refcnt, 1);
+ msg->send_failed = 0;
+ msg->send_error = 0;
+ msg->can_delay = 1;
+ msg->abandoned = 0;
+ msg->expires_at = 0;
+ INIT_LIST_HEAD(&msg->chunks);
+}
+
+/* Allocate and initialize datamsg. */
+static struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp)
+{
+ struct sctp_datamsg *msg;
+ msg = kmalloc(sizeof(struct sctp_datamsg), gfp);
+ if (msg) {
+ sctp_datamsg_init(msg);
+ SCTP_DBG_OBJCNT_INC(datamsg);
+ }
+ return msg;
+}
+
+void sctp_datamsg_free(struct sctp_datamsg *msg)
+{
+ struct sctp_chunk *chunk;
+
+ /* This doesn't have to be a _safe vairant because
+ * sctp_chunk_free() only drops the refs.
+ */
+ list_for_each_entry(chunk, &msg->chunks, frag_list)
+ sctp_chunk_free(chunk);
+
+ sctp_datamsg_put(msg);
+}
+
+/* Final destructruction of datamsg memory. */
+static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
+{
+ struct sctp_association *asoc = NULL;
+ struct list_head *pos, *temp;
+ struct sctp_chunk *chunk;
+ struct sctp_ulpevent *ev;
+ int error, sent;
+
+ /* Release all references. */
+ list_for_each_safe(pos, temp, &msg->chunks) {
+ list_del_init(pos);
+ chunk = list_entry(pos, struct sctp_chunk, frag_list);
+
+ if (!msg->send_failed) {
+ sctp_chunk_put(chunk);
+ continue;
+ }
+
+ asoc = chunk->asoc;
+ error = msg->send_error ?: asoc->outqueue.error;
+ sent = chunk->has_tsn ? SCTP_DATA_SENT : SCTP_DATA_UNSENT;
+
+ if (sctp_ulpevent_type_enabled(asoc->subscribe,
+ SCTP_SEND_FAILED)) {
+ ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
+ error, GFP_ATOMIC);
+ if (ev)
+ asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
+ }
+
+ if (sctp_ulpevent_type_enabled(asoc->subscribe,
+ SCTP_SEND_FAILED_EVENT)) {
+ ev = sctp_ulpevent_make_send_failed_event(asoc, chunk,
+ sent, error,
+ GFP_ATOMIC);
+ if (ev)
+ asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
+ }
+
+ sctp_chunk_put(chunk);
+ }
+
+ SCTP_DBG_OBJCNT_DEC(datamsg);
+ kfree(msg);
+}
+
+/* Hold a reference. */
+static void sctp_datamsg_hold(struct sctp_datamsg *msg)
+{
+ refcount_inc(&msg->refcnt);
+}
+
+/* Release a reference. */
+void sctp_datamsg_put(struct sctp_datamsg *msg)
+{
+ if (refcount_dec_and_test(&msg->refcnt))
+ sctp_datamsg_destroy(msg);
+}
+
+/* Assign a chunk to this datamsg. */
+static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
+{
+ sctp_datamsg_hold(msg);
+ chunk->msg = msg;
+}
+
+
+/* A data chunk can have a maximum payload of (2^16 - 20). Break
+ * down any such message into smaller chunks. Opportunistically, fragment
+ * the chunks down to the current MTU constraints. We may get refragmented
+ * later if the PMTU changes, but it is _much better_ to fragment immediately
+ * with a reasonable guess than always doing our fragmentation on the
+ * soft-interrupt.
+ */
+struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
+ struct sctp_sndrcvinfo *sinfo,
+ struct iov_iter *from)
+{
+ size_t len, first_len, max_data, remaining;
+ size_t msg_len = iov_iter_count(from);
+ struct sctp_shared_key *shkey = NULL;
+ struct list_head *pos, *temp;
+ struct sctp_chunk *chunk;
+ struct sctp_datamsg *msg;
+ int err;
+
+ msg = sctp_datamsg_new(GFP_KERNEL);
+ if (!msg)
+ return ERR_PTR(-ENOMEM);
+
+ /* Note: Calculate this outside of the loop, so that all fragments
+ * have the same expiration.
+ */
+ if (asoc->peer.prsctp_capable && sinfo->sinfo_timetolive &&
+ (SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags) ||
+ !SCTP_PR_POLICY(sinfo->sinfo_flags)))
+ msg->expires_at = jiffies +
+ msecs_to_jiffies(sinfo->sinfo_timetolive);
+
+ /* This is the biggest possible DATA chunk that can fit into
+ * the packet
+ */
+ max_data = asoc->frag_point;
+ if (unlikely(!max_data)) {
+ max_data = sctp_min_frag_point(sctp_sk(asoc->base.sk),
+ sctp_datachk_len(&asoc->stream));
+ pr_warn_ratelimited("%s: asoc:%p frag_point is zero, forcing max_data to default minimum (%zu)",
+ __func__, asoc, max_data);
+ }
+
+ /* If the peer requested that we authenticate DATA chunks
+ * we need to account for bundling of the AUTH chunks along with
+ * DATA.
+ */
+ if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) {
+ struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
+
+ if (hmac_desc)
+ max_data -= SCTP_PAD4(sizeof(struct sctp_auth_chunk) +
+ hmac_desc->hmac_len);
+
+ if (sinfo->sinfo_tsn &&
+ sinfo->sinfo_ssn != asoc->active_key_id) {
+ shkey = sctp_auth_get_shkey(asoc, sinfo->sinfo_ssn);
+ if (!shkey) {
+ err = -EINVAL;
+ goto errout;
+ }
+ } else {
+ shkey = asoc->shkey;
+ }
+ }
+
+ /* Set first_len and then account for possible bundles on first frag */
+ first_len = max_data;
+
+ /* Check to see if we have a pending SACK and try to let it be bundled
+ * with this message. Do this if we don't have any data queued already.
+ * To check that, look at out_qlen and retransmit list.
+ * NOTE: we will not reduce to account for SACK, if the message would
+ * not have been fragmented.
+ */
+ if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) &&
+ asoc->outqueue.out_qlen == 0 &&
+ list_empty(&asoc->outqueue.retransmit) &&
+ msg_len > max_data)
+ first_len -= SCTP_PAD4(sizeof(struct sctp_sack_chunk));
+
+ /* Encourage Cookie-ECHO bundling. */
+ if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
+ first_len -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;
+
+ /* Account for a different sized first fragment */
+ if (msg_len >= first_len) {
+ msg->can_delay = 0;
+ if (msg_len > first_len)
+ SCTP_INC_STATS(asoc->base.net,
+ SCTP_MIB_FRAGUSRMSGS);
+ } else {
+ /* Which may be the only one... */
+ first_len = msg_len;
+ }
+
+ /* Create chunks for all DATA chunks. */
+ for (remaining = msg_len; remaining; remaining -= len) {
+ u8 frag = SCTP_DATA_MIDDLE_FRAG;
+
+ if (remaining == msg_len) {
+ /* First frag, which may also be the last */
+ frag |= SCTP_DATA_FIRST_FRAG;
+ len = first_len;
+ } else {
+ /* Middle frags */
+ len = max_data;
+ }
+
+ if (len >= remaining) {
+ /* Last frag, which may also be the first */
+ len = remaining;
+ frag |= SCTP_DATA_LAST_FRAG;
+
+ /* The application requests to set the I-bit of the
+ * last DATA chunk of a user message when providing
+ * the user message to the SCTP implementation.
+ */
+ if ((sinfo->sinfo_flags & SCTP_EOF) ||
+ (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
+ frag |= SCTP_DATA_SACK_IMM;
+ }
+
+ chunk = asoc->stream.si->make_datafrag(asoc, sinfo, len, frag,
+ GFP_KERNEL);
+ if (!chunk) {
+ err = -ENOMEM;
+ goto errout;
+ }
+
+ err = sctp_user_addto_chunk(chunk, len, from);
+ if (err < 0)
+ goto errout_chunk_free;
+
+ chunk->shkey = shkey;
+
+ /* Put the chunk->skb back into the form expected by send. */
+ __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr -
+ chunk->skb->data);
+
+ sctp_datamsg_assign(msg, chunk);
+ list_add_tail(&chunk->frag_list, &msg->chunks);
+ }
+
+ return msg;
+
+errout_chunk_free:
+ sctp_chunk_free(chunk);
+
+errout:
+ list_for_each_safe(pos, temp, &msg->chunks) {
+ list_del_init(pos);
+ chunk = list_entry(pos, struct sctp_chunk, frag_list);
+ sctp_chunk_free(chunk);
+ }
+ sctp_datamsg_put(msg);
+
+ return ERR_PTR(err);
+}
+
+/* Check whether this message has expired. */
+int sctp_chunk_abandoned(struct sctp_chunk *chunk)
+{
+ if (!chunk->asoc->peer.prsctp_capable)
+ return 0;
+
+ if (chunk->msg->abandoned)
+ return 1;
+
+ if (!chunk->has_tsn &&
+ !(chunk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG))
+ return 0;
+
+ if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) &&
+ time_after(jiffies, chunk->msg->expires_at)) {
+ struct sctp_stream_out *streamout =
+ SCTP_SO(&chunk->asoc->stream,
+ chunk->sinfo.sinfo_stream);
+
+ if (chunk->sent_count) {
+ chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
+ streamout->ext->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
+ } else {
+ chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++;
+ streamout->ext->abandoned_unsent[SCTP_PR_INDEX(TTL)]++;
+ }
+ chunk->msg->abandoned = 1;
+ return 1;
+ } else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) &&
+ chunk->sent_count > chunk->sinfo.sinfo_timetolive) {
+ struct sctp_stream_out *streamout =
+ SCTP_SO(&chunk->asoc->stream,
+ chunk->sinfo.sinfo_stream);
+
+ chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
+ streamout->ext->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
+ chunk->msg->abandoned = 1;
+ return 1;
+ } else if (!SCTP_PR_POLICY(chunk->sinfo.sinfo_flags) &&
+ chunk->msg->expires_at &&
+ time_after(jiffies, chunk->msg->expires_at)) {
+ chunk->msg->abandoned = 1;
+ return 1;
+ }
+ /* PRIO policy is processed by sendmsg, not here */
+
+ return 0;
+}
+
+/* This chunk (and consequently entire message) has failed in its sending. */
+void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
+{
+ chunk->msg->send_failed = 1;
+ chunk->msg->send_error = error;
+}
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