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 /* Properly release the chunk which is being worked on. */ 42 static inline void sctp_inq_chunk_free(struct sctp_chunk *chunk) 43 { 44 if (chunk->head_skb) 45 chunk->skb = chunk->head_skb; 46 sctp_chunk_free(chunk); 47 } 48 49 /* Release the memory associated with an SCTP inqueue. */ 50 void sctp_inq_free(struct sctp_inq *queue) 51 { 52 struct sctp_chunk *chunk, *tmp; 53 54 /* Empty the queue. */ 55 list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) { 56 list_del_init(&chunk->list); 57 sctp_chunk_free(chunk); 58 } 59 60 /* If there is a packet which is currently being worked on, 61 * free it as well. 62 */ 63 if (queue->in_progress) { 64 sctp_inq_chunk_free(queue->in_progress); 65 queue->in_progress = NULL; 66 } 67 } 68 69 /* Put a new packet in an SCTP inqueue. 70 * We assume that packet->sctp_hdr is set and in host byte order. 71 */ 72 void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk) 73 { 74 /* Directly call the packet handling routine. Drop the chunk if the 75 * receiver or the transport it was looked up on is gone. 76 */ 77 if (chunk->rcvr->dead || 78 (chunk->transport && chunk->transport->dead)) { 79 sctp_chunk_free(chunk); 80 return; 81 } 82 83 /* We are now calling this either from the soft interrupt 84 * or from the backlog processing. 85 * Eventually, we should clean up inqueue to not rely 86 * on the BH related data structures. 87 */ 88 list_add_tail(&chunk->list, &q->in_chunk_list); 89 if (chunk->asoc) 90 chunk->asoc->stats.ipackets++; 91 q->immediate.func(&q->immediate); 92 } 93 94 /* Peek at the next chunk on the inqeue. */ 95 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue) 96 { 97 struct sctp_chunk *chunk; 98 struct sctp_chunkhdr *ch = NULL; 99 100 chunk = queue->in_progress; 101 /* If there is no more chunks in this packet, say so */ 102 if (chunk->singleton || 103 chunk->end_of_packet || 104 chunk->pdiscard) 105 return NULL; 106 107 ch = (struct sctp_chunkhdr *)chunk->chunk_end; 108 109 return ch; 110 } 111 112 113 /* Extract a chunk from an SCTP inqueue. 114 * 115 * WARNING: If you need to put the chunk on another queue, you need to 116 * make a shallow copy (clone) of it. 117 */ 118 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue) 119 { 120 struct sctp_chunk *chunk; 121 struct sctp_chunkhdr *ch = NULL; 122 123 /* The assumption is that we are safe to process the chunks 124 * at this time. 125 */ 126 127 chunk = queue->in_progress; 128 if (chunk) { 129 /* There is a packet that we have been working on. 130 * Any post processing work to do before we move on? 131 */ 132 if (chunk->singleton || 133 chunk->end_of_packet || 134 chunk->pdiscard) { 135 if (chunk->head_skb == chunk->skb) { 136 chunk->skb = skb_shinfo(chunk->skb)->frag_list; 137 goto new_skb; 138 } 139 if (chunk->skb->next) { 140 chunk->skb = chunk->skb->next; 141 goto new_skb; 142 } 143 144 sctp_inq_chunk_free(chunk); 145 chunk = queue->in_progress = NULL; 146 } else { 147 /* Nothing to do. Next chunk in the packet, please. */ 148 ch = (struct sctp_chunkhdr *)chunk->chunk_end; 149 /* Force chunk->skb->data to chunk->chunk_end. */ 150 skb_pull(chunk->skb, chunk->chunk_end - chunk->skb->data); 151 /* We are guaranteed to pull a SCTP header. */ 152 } 153 } 154 155 /* Do we need to take the next packet out of the queue to process? */ 156 if (!chunk) { 157 struct list_head *entry; 158 159 next_chunk: 160 /* Is the queue empty? */ 161 entry = sctp_list_dequeue(&queue->in_chunk_list); 162 if (!entry) 163 return NULL; 164 165 chunk = list_entry(entry, struct sctp_chunk, list); 166 167 if (skb_is_gso(chunk->skb) && skb_is_gso_sctp(chunk->skb)) { 168 /* GSO-marked skbs but without frags, handle 169 * them normally 170 */ 171 if (skb_shinfo(chunk->skb)->frag_list) 172 chunk->head_skb = chunk->skb; 173 174 /* skbs with "cover letter" */ 175 if (chunk->head_skb && chunk->skb->data_len == chunk->skb->len) { 176 if (WARN_ON(!skb_shinfo(chunk->skb)->frag_list)) { 177 __SCTP_INC_STATS(dev_net(chunk->skb->dev), 178 SCTP_MIB_IN_PKT_DISCARDS); 179 sctp_chunk_free(chunk); 180 goto next_chunk; 181 } 182 chunk->skb = skb_shinfo(chunk->skb)->frag_list; 183 } 184 } 185 186 if (chunk->asoc) 187 sock_rps_save_rxhash(chunk->asoc->base.sk, chunk->skb); 188 189 queue->in_progress = chunk; 190 191 new_skb: 192 /* This is the first chunk in the packet. */ 193 ch = (struct sctp_chunkhdr *)chunk->skb->data; 194 chunk->singleton = 1; 195 chunk->data_accepted = 0; 196 chunk->pdiscard = 0; 197 chunk->auth = 0; 198 chunk->has_asconf = 0; 199 chunk->end_of_packet = 0; 200 if (chunk->head_skb) { 201 struct sctp_input_cb 202 *cb = SCTP_INPUT_CB(chunk->skb), 203 *head_cb = SCTP_INPUT_CB(chunk->head_skb); 204 205 cb->chunk = head_cb->chunk; 206 cb->af = head_cb->af; 207 cb->encap_port = head_cb->encap_port; 208 } 209 } 210 211 chunk->chunk_hdr = ch; 212 chunk->chunk_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 213 skb_pull(chunk->skb, sizeof(*ch)); 214 chunk->subh.v = NULL; /* Subheader is no longer valid. */ 215 216 if (chunk->chunk_end + sizeof(*ch) <= skb_tail_pointer(chunk->skb)) { 217 /* This is not a singleton */ 218 chunk->singleton = 0; 219 } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) { 220 /* Discard inside state machine. */ 221 chunk->pdiscard = 1; 222 chunk->chunk_end = skb_tail_pointer(chunk->skb); 223 } else { 224 /* We are at the end of the packet, so mark the chunk 225 * in case we need to send a SACK. 226 */ 227 chunk->end_of_packet = 1; 228 } 229 230 pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n", 231 chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), 232 ntohs(chunk->chunk_hdr->length), chunk->skb->len); 233 234 return chunk; 235 } 236 237 /* Set a top-half handler. 238 * 239 * Originally, we the top-half handler was scheduled as a BH. We now 240 * call the handler directly in sctp_inq_push() at a time that 241 * we know we are lock safe. 242 * The intent is that this routine will pull stuff out of the 243 * inqueue and process it. 244 */ 245 void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback) 246 { 247 INIT_WORK(&q->immediate, callback); 248 } 249