1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* SCTP kernel implementation 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2002 International Business Machines, Corp. 6 * 7 * This file is part of the SCTP kernel implementation 8 * 9 * These functions are the methods for accessing the SCTP inqueue. 10 * 11 * An SCTP inqueue is a queue into which you push SCTP packets 12 * (which might be bundles or fragments of chunks) and out of which you 13 * pop SCTP whole chunks. 14 * 15 * Please send any bug reports or fixes you make to the 16 * email address(es): 17 * lksctp developers <linux-sctp@vger.kernel.org> 18 * 19 * Written or modified by: 20 * La Monte H.P. Yarroll <piggy@acm.org> 21 * Karl Knutson <karl@athena.chicago.il.us> 22 */ 23 24 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 25 26 #include <net/sctp/sctp.h> 27 #include <net/sctp/sm.h> 28 #include <linux/interrupt.h> 29 #include <linux/slab.h> 30 31 /* Initialize an SCTP inqueue. */ 32 void sctp_inq_init(struct sctp_inq *queue) 33 { 34 INIT_LIST_HEAD(&queue->in_chunk_list); 35 queue->in_progress = NULL; 36 37 /* Create a task for delivering data. */ 38 INIT_WORK(&queue->immediate, NULL); 39 } 40 41 /* Release the memory associated with an SCTP inqueue. */ 42 void sctp_inq_free(struct sctp_inq *queue) 43 { 44 struct sctp_chunk *chunk, *tmp; 45 46 /* Empty the queue. */ 47 list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) { 48 list_del_init(&chunk->list); 49 sctp_chunk_free(chunk); 50 } 51 52 /* If there is a packet which is currently being worked on, 53 * free it as well. 54 */ 55 if (queue->in_progress) { 56 sctp_chunk_free(queue->in_progress); 57 queue->in_progress = NULL; 58 } 59 } 60 61 /* Put a new packet in an SCTP inqueue. 62 * We assume that packet->sctp_hdr is set and in host byte order. 63 */ 64 void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk) 65 { 66 /* Directly call the packet handling routine. */ 67 if (chunk->rcvr->dead) { 68 sctp_chunk_free(chunk); 69 return; 70 } 71 72 /* We are now calling this either from the soft interrupt 73 * or from the backlog processing. 74 * Eventually, we should clean up inqueue to not rely 75 * on the BH related data structures. 76 */ 77 list_add_tail(&chunk->list, &q->in_chunk_list); 78 if (chunk->asoc) 79 chunk->asoc->stats.ipackets++; 80 q->immediate.func(&q->immediate); 81 } 82 83 /* Peek at the next chunk on the inqeue. */ 84 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue) 85 { 86 struct sctp_chunk *chunk; 87 struct sctp_chunkhdr *ch = NULL; 88 89 chunk = queue->in_progress; 90 /* If there is no more chunks in this packet, say so */ 91 if (chunk->singleton || 92 chunk->end_of_packet || 93 chunk->pdiscard) 94 return NULL; 95 96 ch = (struct sctp_chunkhdr *)chunk->chunk_end; 97 98 return ch; 99 } 100 101 102 /* Extract a chunk from an SCTP inqueue. 103 * 104 * WARNING: If you need to put the chunk on another queue, you need to 105 * make a shallow copy (clone) of it. 106 */ 107 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue) 108 { 109 struct sctp_chunk *chunk; 110 struct sctp_chunkhdr *ch = NULL; 111 112 /* The assumption is that we are safe to process the chunks 113 * at this time. 114 */ 115 116 chunk = queue->in_progress; 117 if (chunk) { 118 /* There is a packet that we have been working on. 119 * Any post processing work to do before we move on? 120 */ 121 if (chunk->singleton || 122 chunk->end_of_packet || 123 chunk->pdiscard) { 124 if (chunk->head_skb == chunk->skb) { 125 chunk->skb = skb_shinfo(chunk->skb)->frag_list; 126 goto new_skb; 127 } 128 if (chunk->skb->next) { 129 chunk->skb = chunk->skb->next; 130 goto new_skb; 131 } 132 133 if (chunk->head_skb) 134 chunk->skb = chunk->head_skb; 135 sctp_chunk_free(chunk); 136 chunk = queue->in_progress = NULL; 137 } else { 138 /* Nothing to do. Next chunk in the packet, please. */ 139 ch = (struct sctp_chunkhdr *)chunk->chunk_end; 140 /* Force chunk->skb->data to chunk->chunk_end. */ 141 skb_pull(chunk->skb, chunk->chunk_end - chunk->skb->data); 142 /* We are guaranteed to pull a SCTP header. */ 143 } 144 } 145 146 /* Do we need to take the next packet out of the queue to process? */ 147 if (!chunk) { 148 struct list_head *entry; 149 150 next_chunk: 151 /* Is the queue empty? */ 152 entry = sctp_list_dequeue(&queue->in_chunk_list); 153 if (!entry) 154 return NULL; 155 156 chunk = list_entry(entry, struct sctp_chunk, list); 157 158 if (skb_is_gso(chunk->skb) && skb_is_gso_sctp(chunk->skb)) { 159 /* GSO-marked skbs but without frags, handle 160 * them normally 161 */ 162 if (skb_shinfo(chunk->skb)->frag_list) 163 chunk->head_skb = chunk->skb; 164 165 /* skbs with "cover letter" */ 166 if (chunk->head_skb && chunk->skb->data_len == chunk->skb->len) 167 chunk->skb = skb_shinfo(chunk->skb)->frag_list; 168 169 if (WARN_ON(!chunk->skb)) { 170 __SCTP_INC_STATS(dev_net(chunk->skb->dev), SCTP_MIB_IN_PKT_DISCARDS); 171 sctp_chunk_free(chunk); 172 goto next_chunk; 173 } 174 } 175 176 if (chunk->asoc) 177 sock_rps_save_rxhash(chunk->asoc->base.sk, chunk->skb); 178 179 queue->in_progress = chunk; 180 181 new_skb: 182 /* This is the first chunk in the packet. */ 183 ch = (struct sctp_chunkhdr *)chunk->skb->data; 184 chunk->singleton = 1; 185 chunk->data_accepted = 0; 186 chunk->pdiscard = 0; 187 chunk->auth = 0; 188 chunk->has_asconf = 0; 189 chunk->end_of_packet = 0; 190 if (chunk->head_skb) { 191 struct sctp_input_cb 192 *cb = SCTP_INPUT_CB(chunk->skb), 193 *head_cb = SCTP_INPUT_CB(chunk->head_skb); 194 195 cb->chunk = head_cb->chunk; 196 cb->af = head_cb->af; 197 } 198 } 199 200 chunk->chunk_hdr = ch; 201 chunk->chunk_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 202 skb_pull(chunk->skb, sizeof(*ch)); 203 chunk->subh.v = NULL; /* Subheader is no longer valid. */ 204 205 if (chunk->chunk_end + sizeof(*ch) <= skb_tail_pointer(chunk->skb)) { 206 /* This is not a singleton */ 207 chunk->singleton = 0; 208 } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) { 209 /* Discard inside state machine. */ 210 chunk->pdiscard = 1; 211 chunk->chunk_end = skb_tail_pointer(chunk->skb); 212 } else { 213 /* We are at the end of the packet, so mark the chunk 214 * in case we need to send a SACK. 215 */ 216 chunk->end_of_packet = 1; 217 } 218 219 pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n", 220 chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), 221 ntohs(chunk->chunk_hdr->length), chunk->skb->len); 222 223 return chunk; 224 } 225 226 /* Set a top-half handler. 227 * 228 * Originally, we the top-half handler was scheduled as a BH. We now 229 * call the handler directly in sctp_inq_push() at a time that 230 * we know we are lock safe. 231 * The intent is that this routine will pull stuff out of the 232 * inqueue and process it. 233 */ 234 void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback) 235 { 236 INIT_WORK(&q->immediate, callback); 237 } 238