diff options
Diffstat (limited to 'net/sctp/chunk.c')
| -rw-r--r-- | net/sctp/chunk.c | 365 |
1 files changed, 365 insertions, 0 deletions
diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c new file mode 100644 index 000000000..a3380917f --- /dev/null +++ b/net/sctp/chunk.c @@ -0,0 +1,365 @@ +/* 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; +} |