/* 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_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 (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->pathmtu - sctp_sk(asoc->base.sk)->pf->af->net_header_len - sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk); max_data = SCTP_TRUNC4(max_data); 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 -= SCTP_PAD4(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 -= SCTP_PAD4(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(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, GFP_KERNEL); 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, GFP_KERNEL); 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) { if (!chunk->asoc->peer.prsctp_capable) return 0; if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) && time_after(jiffies, chunk->msg->expires_at)) { if (chunk->sent_count) chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++; else chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; return 1; } else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) && chunk->sent_count > chunk->sinfo.sinfo_timetolive) { chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++; return 1; } else if (!SCTP_PR_POLICY(chunk->sinfo.sinfo_flags) && chunk->msg->expires_at && time_after(jiffies, chunk->msg->expires_at)) { 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; }