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![Tommi Rantala](/assets/img/avatar_default.png)
Consider the following program, that sets the second argument to the sendto() syscall incorrectly: #include <string.h> #include <arpa/inet.h> #include <sys/socket.h> int main(void) { int fd; struct sockaddr_in sa; fd = socket(AF_INET, SOCK_STREAM, 132 /*IPPROTO_SCTP*/); if (fd < 0) return 1; memset(&sa, 0, sizeof(sa)); sa.sin_family = AF_INET; sa.sin_addr.s_addr = inet_addr("127.0.0.1"); sa.sin_port = htons(11111); sendto(fd, NULL, 1, 0, (struct sockaddr *)&sa, sizeof(sa)); return 0; } We get -ENOMEM: $ strace -e sendto ./demo sendto(3, NULL, 1, 0, {sa_family=AF_INET, sin_port=htons(11111), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 ENOMEM (Cannot allocate memory) Propagate the error code from sctp_user_addto_chunk(), so that we will tell user space what actually went wrong: $ strace -e sendto ./demo sendto(3, NULL, 1, 0, {sa_family=AF_INET, sin_port=htons(11111), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 EFAULT (Bad address) Noticed while running Trinity (the syscall fuzzer). Signed-off-by: Tommi Rantala <tt.rantala@gmail.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
372 lines
9.8 KiB
C
372 lines
9.8 KiB
C
/* SCTP kernel implementation
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* (C) Copyright IBM Corp. 2003, 2004
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*
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* This file is part of the SCTP kernel implementation
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*
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* This file contains the code relating the chunk abstraction.
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*
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* This SCTP implementation is free software;
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* you can redistribute it and/or modify it under the terms of
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* the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This SCTP implementation is distributed in the hope that it
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* will be useful, but WITHOUT ANY WARRANTY; without even the implied
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* ************************
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU CC; see the file COPYING. If not, write to
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* the Free Software Foundation, 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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* Please send any bug reports or fixes you make to the
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* email address(es):
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* lksctp developers <lksctp-developers@lists.sourceforge.net>
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*
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* Or submit a bug report through the following website:
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* http://www.sf.net/projects/lksctp
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*
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* Written or modified by:
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* Jon Grimm <jgrimm@us.ibm.com>
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* Sridhar Samudrala <sri@us.ibm.com>
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*
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* Any bugs reported given to us we will try to fix... any fixes shared will
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* be incorporated into the next SCTP release.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/net.h>
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#include <linux/inet.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <net/sock.h>
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#include <net/sctp/sctp.h>
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#include <net/sctp/sm.h>
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/* This file is mostly in anticipation of future work, but initially
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* populate with fragment tracking for an outbound message.
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*/
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/* Initialize datamsg from memory. */
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static void sctp_datamsg_init(struct sctp_datamsg *msg)
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{
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atomic_set(&msg->refcnt, 1);
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msg->send_failed = 0;
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msg->send_error = 0;
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msg->can_abandon = 0;
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msg->can_delay = 1;
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msg->expires_at = 0;
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INIT_LIST_HEAD(&msg->chunks);
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}
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/* Allocate and initialize datamsg. */
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SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp)
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{
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struct sctp_datamsg *msg;
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msg = kmalloc(sizeof(struct sctp_datamsg), gfp);
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if (msg) {
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sctp_datamsg_init(msg);
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SCTP_DBG_OBJCNT_INC(datamsg);
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}
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return msg;
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}
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void sctp_datamsg_free(struct sctp_datamsg *msg)
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{
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struct sctp_chunk *chunk;
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/* This doesn't have to be a _safe vairant because
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* sctp_chunk_free() only drops the refs.
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*/
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list_for_each_entry(chunk, &msg->chunks, frag_list)
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sctp_chunk_free(chunk);
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sctp_datamsg_put(msg);
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}
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/* Final destructruction of datamsg memory. */
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static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
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{
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struct list_head *pos, *temp;
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struct sctp_chunk *chunk;
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struct sctp_sock *sp;
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struct sctp_ulpevent *ev;
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struct sctp_association *asoc = NULL;
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int error = 0, notify;
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/* If we failed, we may need to notify. */
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notify = msg->send_failed ? -1 : 0;
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/* Release all references. */
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list_for_each_safe(pos, temp, &msg->chunks) {
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list_del_init(pos);
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chunk = list_entry(pos, struct sctp_chunk, frag_list);
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/* Check whether we _really_ need to notify. */
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if (notify < 0) {
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asoc = chunk->asoc;
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if (msg->send_error)
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error = msg->send_error;
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else
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error = asoc->outqueue.error;
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sp = sctp_sk(asoc->base.sk);
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notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED,
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&sp->subscribe);
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}
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/* Generate a SEND FAILED event only if enabled. */
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if (notify > 0) {
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int sent;
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if (chunk->has_tsn)
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sent = SCTP_DATA_SENT;
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else
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sent = SCTP_DATA_UNSENT;
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ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
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error, GFP_ATOMIC);
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if (ev)
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sctp_ulpq_tail_event(&asoc->ulpq, ev);
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}
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sctp_chunk_put(chunk);
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}
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SCTP_DBG_OBJCNT_DEC(datamsg);
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kfree(msg);
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}
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/* Hold a reference. */
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static void sctp_datamsg_hold(struct sctp_datamsg *msg)
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{
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atomic_inc(&msg->refcnt);
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}
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/* Release a reference. */
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void sctp_datamsg_put(struct sctp_datamsg *msg)
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{
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if (atomic_dec_and_test(&msg->refcnt))
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sctp_datamsg_destroy(msg);
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}
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/* Assign a chunk to this datamsg. */
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static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
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{
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sctp_datamsg_hold(msg);
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chunk->msg = msg;
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}
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/* A data chunk can have a maximum payload of (2^16 - 20). Break
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* down any such message into smaller chunks. Opportunistically, fragment
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* the chunks down to the current MTU constraints. We may get refragmented
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* later if the PMTU changes, but it is _much better_ to fragment immediately
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* with a reasonable guess than always doing our fragmentation on the
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* soft-interrupt.
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*/
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struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
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struct sctp_sndrcvinfo *sinfo,
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struct msghdr *msgh, int msg_len)
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{
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int max, whole, i, offset, over, err;
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int len, first_len;
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int max_data;
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struct sctp_chunk *chunk;
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struct sctp_datamsg *msg;
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struct list_head *pos, *temp;
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__u8 frag;
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msg = sctp_datamsg_new(GFP_KERNEL);
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if (!msg)
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return ERR_PTR(-ENOMEM);
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/* Note: Calculate this outside of the loop, so that all fragments
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* have the same expiration.
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*/
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if (sinfo->sinfo_timetolive) {
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/* sinfo_timetolive is in milliseconds */
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msg->expires_at = jiffies +
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msecs_to_jiffies(sinfo->sinfo_timetolive);
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msg->can_abandon = 1;
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SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n",
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__func__, msg, msg->expires_at, jiffies);
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}
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/* This is the biggest possible DATA chunk that can fit into
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* the packet
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*/
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max_data = asoc->pathmtu -
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sctp_sk(asoc->base.sk)->pf->af->net_header_len -
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sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk);
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max = asoc->frag_point;
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/* If the the peer requested that we authenticate DATA chunks
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* we need to accound for bundling of the AUTH chunks along with
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* DATA.
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*/
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if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) {
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struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
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if (hmac_desc)
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max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
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hmac_desc->hmac_len);
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}
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/* Now, check if we need to reduce our max */
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if (max > max_data)
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max = max_data;
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whole = 0;
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first_len = max;
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/* Check to see if we have a pending SACK and try to let it be bundled
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* with this message. Do this if we don't have any data queued already.
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* To check that, look at out_qlen and retransmit list.
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* NOTE: we will not reduce to account for SACK, if the message would
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* not have been fragmented.
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*/
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if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) &&
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asoc->outqueue.out_qlen == 0 &&
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list_empty(&asoc->outqueue.retransmit) &&
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msg_len > max)
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max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t));
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/* Encourage Cookie-ECHO bundling. */
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if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
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max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;
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/* Now that we adjusted completely, reset first_len */
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if (first_len > max_data)
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first_len = max_data;
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/* Account for a different sized first fragment */
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if (msg_len >= first_len) {
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msg_len -= first_len;
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whole = 1;
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msg->can_delay = 0;
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}
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/* How many full sized? How many bytes leftover? */
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whole += msg_len / max;
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over = msg_len % max;
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offset = 0;
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if ((whole > 1) || (whole && over))
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SCTP_INC_STATS_USER(sock_net(asoc->base.sk), SCTP_MIB_FRAGUSRMSGS);
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/* Create chunks for all the full sized DATA chunks. */
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for (i=0, len=first_len; i < whole; i++) {
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frag = SCTP_DATA_MIDDLE_FRAG;
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if (0 == i)
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frag |= SCTP_DATA_FIRST_FRAG;
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if ((i == (whole - 1)) && !over) {
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frag |= SCTP_DATA_LAST_FRAG;
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/* The application requests to set the I-bit of the
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* last DATA chunk of a user message when providing
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* the user message to the SCTP implementation.
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*/
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if ((sinfo->sinfo_flags & SCTP_EOF) ||
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(sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
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frag |= SCTP_DATA_SACK_IMM;
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}
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chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);
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if (!chunk) {
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err = -ENOMEM;
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goto errout;
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}
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err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov);
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if (err < 0)
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goto errout_chunk_free;
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offset += len;
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/* Put the chunk->skb back into the form expected by send. */
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__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
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- (__u8 *)chunk->skb->data);
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sctp_datamsg_assign(msg, chunk);
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list_add_tail(&chunk->frag_list, &msg->chunks);
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/* The first chunk, the first chunk was likely short
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* to allow bundling, so reset to full size.
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*/
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if (0 == i)
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len = max;
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}
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/* .. now the leftover bytes. */
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if (over) {
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if (!whole)
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frag = SCTP_DATA_NOT_FRAG;
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else
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frag = SCTP_DATA_LAST_FRAG;
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if ((sinfo->sinfo_flags & SCTP_EOF) ||
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(sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
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frag |= SCTP_DATA_SACK_IMM;
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chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);
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if (!chunk) {
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err = -ENOMEM;
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goto errout;
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}
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err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov);
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/* Put the chunk->skb back into the form expected by send. */
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__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
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- (__u8 *)chunk->skb->data);
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if (err < 0)
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goto errout_chunk_free;
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sctp_datamsg_assign(msg, chunk);
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list_add_tail(&chunk->frag_list, &msg->chunks);
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}
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return msg;
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errout_chunk_free:
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sctp_chunk_free(chunk);
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errout:
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list_for_each_safe(pos, temp, &msg->chunks) {
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list_del_init(pos);
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chunk = list_entry(pos, struct sctp_chunk, frag_list);
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sctp_chunk_free(chunk);
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}
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sctp_datamsg_put(msg);
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return ERR_PTR(err);
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}
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/* Check whether this message has expired. */
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int sctp_chunk_abandoned(struct sctp_chunk *chunk)
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{
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struct sctp_datamsg *msg = chunk->msg;
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if (!msg->can_abandon)
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return 0;
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if (time_after(jiffies, msg->expires_at))
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return 1;
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return 0;
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}
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/* This chunk (and consequently entire message) has failed in its sending. */
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void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
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{
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chunk->msg->send_failed = 1;
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chunk->msg->send_error = error;
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}
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