--- /dev/null
+/* 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.
+ *
+ * This SCTP implementation 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, or (at your option)
+ * any later version.
+ *
+ * This SCTP implementation is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * ************************
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU CC; see the file COPYING. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * 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)
+{
+ atomic_set(&msg->refcnt, 1);
+ msg->send_failed = 0;
+ msg->send_error = 0;
+ msg->can_abandon = 0;
+ msg->can_delay = 1;
+ 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 list_head *pos, *temp;
+ struct sctp_chunk *chunk;
+ struct sctp_sock *sp;
+ struct sctp_ulpevent *ev;
+ struct sctp_association *asoc = NULL;
+ int error = 0, notify;
+
+ /* If we failed, we may need to notify. */
+ notify = msg->send_failed ? -1 : 0;
+
+ /* Release all references. */
+ list_for_each_safe(pos, temp, &msg->chunks) {
+ list_del_init(pos);
+ chunk = list_entry(pos, struct sctp_chunk, frag_list);
+ /* Check whether we _really_ need to notify. */
+ if (notify < 0) {
+ asoc = chunk->asoc;
+ if (msg->send_error)
+ error = msg->send_error;
+ else
+ error = asoc->outqueue.error;
+
+ sp = sctp_sk(asoc->base.sk);
+ notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED,
+ &sp->subscribe);
+ }
+
+ /* Generate a SEND FAILED event only if enabled. */
+ if (notify > 0) {
+ int sent;
+ if (chunk->has_tsn)
+ sent = SCTP_DATA_SENT;
+ else
+ sent = SCTP_DATA_UNSENT;
+
+ ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
+ error, GFP_ATOMIC);
+ if (ev)
+ sctp_ulpq_tail_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)
+{
+ atomic_inc(&msg->refcnt);
+}
+
+/* Release a reference. */
+void sctp_datamsg_put(struct sctp_datamsg *msg)
+{
+ if (atomic_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)
+{
+ int max, whole, i, offset, over, err;
+ int len, first_len;
+ int max_data;
+ struct sctp_chunk *chunk;
+ struct sctp_datamsg *msg;
+ struct list_head *pos, *temp;
+ size_t msg_len = iov_iter_count(from);
+ __u8 frag;
+
+ 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 (sinfo->sinfo_timetolive) {
+ /* sinfo_timetolive is in milliseconds */
+ msg->expires_at = jiffies +
+ msecs_to_jiffies(sinfo->sinfo_timetolive);
+ msg->can_abandon = 1;
+
+ pr_debug("%s: msg:%p expires_at:%ld jiffies:%ld\n", __func__,
+ msg, msg->expires_at, jiffies);
+ }
+
+ /* This is the biggest possible DATA chunk that can fit into
+ * the packet
+ */
+ max_data = (asoc->pathmtu -
+ sctp_sk(asoc->base.sk)->pf->af->net_header_len -
+ sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk)) & ~3;
+
+ max = asoc->frag_point;
+ /* If the 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 -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
+ hmac_desc->hmac_len);
+ }
+
+ /* Now, check if we need to reduce our max */
+ if (max > max_data)
+ max = max_data;
+
+ whole = 0;
+ first_len = max;
+
+ /* 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)
+ max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t));
+
+ /* Encourage Cookie-ECHO bundling. */
+ if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
+ max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;
+
+ /* Now that we adjusted completely, reset first_len */
+ if (first_len > max_data)
+ first_len = max_data;
+
+ /* Account for a different sized first fragment */
+ if (msg_len >= first_len) {
+ msg_len -= first_len;
+ whole = 1;
+ msg->can_delay = 0;
+ }
+
+ /* How many full sized? How many bytes leftover? */
+ whole += msg_len / max;
+ over = msg_len % max;
+ offset = 0;
+
+ if ((whole > 1) || (whole && over))
+ SCTP_INC_STATS_USER(sock_net(asoc->base.sk), SCTP_MIB_FRAGUSRMSGS);
+
+ /* Create chunks for all the full sized DATA chunks. */
+ for (i = 0, len = first_len; i < whole; i++) {
+ frag = SCTP_DATA_MIDDLE_FRAG;
+
+ if (0 == i)
+ frag |= SCTP_DATA_FIRST_FRAG;
+
+ if ((i == (whole - 1)) && !over) {
+ 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 = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);
+
+ if (!chunk) {
+ err = -ENOMEM;
+ goto errout;
+ }
+
+ err = sctp_user_addto_chunk(chunk, len, from);
+ if (err < 0)
+ goto errout_chunk_free;
+
+ /* Put the chunk->skb back into the form expected by send. */
+ __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
+ - (__u8 *)chunk->skb->data);
+
+ sctp_datamsg_assign(msg, chunk);
+ list_add_tail(&chunk->frag_list, &msg->chunks);
+
+ /* The first chunk, the first chunk was likely short
+ * to allow bundling, so reset to full size.
+ */
+ if (0 == i)
+ len = max;
+ }
+
+ /* .. now the leftover bytes. */
+ if (over) {
+ if (!whole)
+ frag = SCTP_DATA_NOT_FRAG;
+ else
+ frag = SCTP_DATA_LAST_FRAG;
+
+ if ((sinfo->sinfo_flags & SCTP_EOF) ||
+ (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
+ frag |= SCTP_DATA_SACK_IMM;
+
+ chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);
+
+ if (!chunk) {
+ err = -ENOMEM;
+ goto errout;
+ }
+
+ err = sctp_user_addto_chunk(chunk, over, from);
+
+ /* Put the chunk->skb back into the form expected by send. */
+ __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
+ - (__u8 *)chunk->skb->data);
+ if (err < 0)
+ goto errout_chunk_free;
+
+ 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)
+{
+ struct sctp_datamsg *msg = chunk->msg;
+
+ if (!msg->can_abandon)
+ return 0;
+
+ if (time_after(jiffies, msg->expires_at))
+ return 1;
+
+ 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;
+}
Code Review / kvmfornfv.git / blobdiff