Subash Abhinov Kasiviswanathan | 2139ce8a | 2016-10-14 11:01:48 -0600 | [diff] [blame] | 1 | /* Copyright (c) 2013-2016, The Linux Foundation. All rights reserved. |
| 2 | * |
| 3 | * This program is free software; you can redistribute it and/or modify |
| 4 | * it under the terms of the GNU General Public License version 2 and |
| 5 | * only version 2 as published by the Free Software Foundation. |
| 6 | * |
| 7 | * This program is distributed in the hope that it will be useful, |
| 8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 10 | * GNU General Public License for more details. |
| 11 | * |
| 12 | * RMNET Data MAP protocol |
| 13 | */ |
| 14 | |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/skbuff.h> |
| 18 | #include <linux/netdevice.h> |
| 19 | #include <linux/rmnet_data.h> |
| 20 | #include <linux/spinlock.h> |
| 21 | #include <linux/workqueue.h> |
| 22 | #include <linux/time.h> |
| 23 | #include <linux/net_map.h> |
| 24 | #include <linux/ip.h> |
| 25 | #include <linux/ipv6.h> |
| 26 | #include <linux/udp.h> |
| 27 | #include <linux/tcp.h> |
| 28 | #include <linux/in.h> |
| 29 | #include <net/ip.h> |
| 30 | #include <net/checksum.h> |
| 31 | #include <net/ip6_checksum.h> |
| 32 | #include <net/rmnet_config.h> |
| 33 | #include "rmnet_data_config.h" |
| 34 | #include "rmnet_map.h" |
| 35 | #include "rmnet_data_private.h" |
| 36 | #include "rmnet_data_stats.h" |
| 37 | #include "rmnet_data_trace.h" |
| 38 | |
| 39 | RMNET_LOG_MODULE(RMNET_DATA_LOGMASK_MAPD); |
| 40 | |
| 41 | /* Local Definitions */ |
| 42 | |
| 43 | long agg_time_limit __read_mostly = 1000000L; |
| 44 | module_param(agg_time_limit, long, 0644); |
| 45 | MODULE_PARM_DESC(agg_time_limit, "Maximum time packets sit in the agg buf"); |
| 46 | |
| 47 | long agg_bypass_time __read_mostly = 10000000L; |
| 48 | module_param(agg_bypass_time, long, 0644); |
| 49 | MODULE_PARM_DESC(agg_bypass_time, "Skip agg when apart spaced more than this"); |
| 50 | |
| 51 | struct agg_work { |
| 52 | struct delayed_work work; |
| 53 | struct rmnet_phys_ep_config *config; |
| 54 | }; |
| 55 | |
| 56 | #define RMNET_MAP_DEAGGR_SPACING 64 |
| 57 | #define RMNET_MAP_DEAGGR_HEADROOM (RMNET_MAP_DEAGGR_SPACING / 2) |
| 58 | |
| 59 | /* rmnet_map_add_map_header() - Adds MAP header to front of skb->data |
| 60 | * @skb: Socket buffer ("packet") to modify |
| 61 | * @hdrlen: Number of bytes of header data which should not be included in |
| 62 | * MAP length field |
| 63 | * @pad: Specify if padding the MAP packet to make it 4 byte aligned is |
| 64 | * necessary |
| 65 | * |
| 66 | * Padding is calculated and set appropriately in MAP header. Mux ID is |
| 67 | * initialized to 0. |
| 68 | * |
| 69 | * Return: |
| 70 | * - Pointer to MAP structure |
| 71 | * - 0 (null) if insufficient headroom |
| 72 | * - 0 (null) if insufficient tailroom for padding bytes |
| 73 | */ |
| 74 | struct rmnet_map_header_s *rmnet_map_add_map_header(struct sk_buff *skb, |
| 75 | int hdrlen, int pad) |
| 76 | { |
| 77 | u32 padding, map_datalen; |
| 78 | u8 *padbytes; |
| 79 | struct rmnet_map_header_s *map_header; |
| 80 | |
| 81 | if (skb_headroom(skb) < sizeof(struct rmnet_map_header_s)) |
| 82 | return 0; |
| 83 | |
| 84 | map_datalen = skb->len - hdrlen; |
| 85 | map_header = (struct rmnet_map_header_s *) |
| 86 | skb_push(skb, sizeof(struct rmnet_map_header_s)); |
| 87 | memset(map_header, 0, sizeof(struct rmnet_map_header_s)); |
| 88 | |
| 89 | if (pad == RMNET_MAP_NO_PAD_BYTES) { |
| 90 | map_header->pkt_len = htons(map_datalen); |
| 91 | return map_header; |
| 92 | } |
| 93 | |
| 94 | padding = ALIGN(map_datalen, 4) - map_datalen; |
| 95 | |
| 96 | if (padding == 0) |
| 97 | goto done; |
| 98 | |
| 99 | if (skb_tailroom(skb) < padding) |
| 100 | return 0; |
| 101 | |
| 102 | padbytes = (u8 *)skb_put(skb, padding); |
| 103 | LOGD("pad: %d", padding); |
| 104 | memset(padbytes, 0, padding); |
| 105 | |
| 106 | done: |
| 107 | map_header->pkt_len = htons(map_datalen + padding); |
| 108 | map_header->pad_len = padding & 0x3F; |
| 109 | |
| 110 | return map_header; |
| 111 | } |
| 112 | |
| 113 | /* rmnet_map_deaggregate() - Deaggregates a single packet |
| 114 | * @skb: Source socket buffer containing multiple MAP frames |
| 115 | * @config: Physical endpoint configuration of the ingress device |
| 116 | * |
| 117 | * A whole new buffer is allocated for each portion of an aggregated frame. |
| 118 | * Caller should keep calling deaggregate() on the source skb until 0 is |
| 119 | * returned, indicating that there are no more packets to deaggregate. Caller |
| 120 | * is responsible for freeing the original skb. |
| 121 | * |
| 122 | * Return: |
| 123 | * - Pointer to new skb |
| 124 | * - 0 (null) if no more aggregated packets |
| 125 | */ |
| 126 | struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb, |
| 127 | struct rmnet_phys_ep_config *config) |
| 128 | { |
| 129 | struct sk_buff *skbn; |
| 130 | struct rmnet_map_header_s *maph; |
| 131 | u32 packet_len; |
| 132 | |
| 133 | if (skb->len == 0) |
| 134 | return 0; |
| 135 | |
| 136 | maph = (struct rmnet_map_header_s *)skb->data; |
| 137 | packet_len = ntohs(maph->pkt_len) + sizeof(struct rmnet_map_header_s); |
| 138 | |
| 139 | if ((config->ingress_data_format & RMNET_INGRESS_FORMAT_MAP_CKSUMV3) || |
| 140 | (config->ingress_data_format & RMNET_INGRESS_FORMAT_MAP_CKSUMV4)) |
| 141 | packet_len += sizeof(struct rmnet_map_dl_checksum_trailer_s); |
| 142 | |
| 143 | if ((((int)skb->len) - ((int)packet_len)) < 0) { |
| 144 | LOGM("%s", "Got malformed packet. Dropping"); |
| 145 | return 0; |
| 146 | } |
| 147 | |
| 148 | skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC); |
| 149 | if (!skbn) |
| 150 | return 0; |
| 151 | |
| 152 | skbn->dev = skb->dev; |
| 153 | skb_reserve(skbn, RMNET_MAP_DEAGGR_HEADROOM); |
| 154 | skb_put(skbn, packet_len); |
| 155 | memcpy(skbn->data, skb->data, packet_len); |
| 156 | skb_pull(skb, packet_len); |
| 157 | |
| 158 | /* Some hardware can send us empty frames. Catch them */ |
| 159 | if (ntohs(maph->pkt_len) == 0) { |
| 160 | LOGD("Dropping empty MAP frame"); |
| 161 | rmnet_kfree_skb(skbn, RMNET_STATS_SKBFREE_DEAGG_DATA_LEN_0); |
| 162 | return 0; |
| 163 | } |
| 164 | |
| 165 | return skbn; |
| 166 | } |
| 167 | |
| 168 | /* rmnet_map_flush_packet_queue() - Transmits aggregeted frame on timeout |
| 169 | * @work: struct agg_work containing delayed work and skb to flush |
| 170 | * |
| 171 | * This function is scheduled to run in a specified number of jiffies after |
| 172 | * the last frame transmitted by the network stack. When run, the buffer |
| 173 | * containing aggregated packets is finally transmitted on the underlying link. |
| 174 | * |
| 175 | */ |
| 176 | static void rmnet_map_flush_packet_queue(struct work_struct *work) |
| 177 | { |
| 178 | struct agg_work *real_work; |
| 179 | struct rmnet_phys_ep_config *config; |
| 180 | unsigned long flags; |
| 181 | struct sk_buff *skb; |
| 182 | int rc, agg_count = 0; |
| 183 | |
| 184 | skb = 0; |
| 185 | real_work = (struct agg_work *)work; |
| 186 | config = real_work->config; |
| 187 | LOGD("%s", "Entering flush thread"); |
| 188 | spin_lock_irqsave(&config->agg_lock, flags); |
| 189 | if (likely(config->agg_state == RMNET_MAP_TXFER_SCHEDULED)) { |
| 190 | /* Buffer may have already been shipped out */ |
| 191 | if (likely(config->agg_skb)) { |
| 192 | rmnet_stats_agg_pkts(config->agg_count); |
| 193 | if (config->agg_count > 1) |
| 194 | LOGL("Agg count: %d", config->agg_count); |
| 195 | skb = config->agg_skb; |
| 196 | agg_count = config->agg_count; |
| 197 | config->agg_skb = 0; |
| 198 | config->agg_count = 0; |
| 199 | memset(&config->agg_time, 0, sizeof(struct timespec)); |
| 200 | } |
| 201 | config->agg_state = RMNET_MAP_AGG_IDLE; |
| 202 | } else { |
| 203 | /* How did we get here? */ |
| 204 | LOGE("Ran queued command when state %s", |
| 205 | "is idle. State machine likely broken"); |
| 206 | } |
| 207 | |
| 208 | spin_unlock_irqrestore(&config->agg_lock, flags); |
| 209 | if (skb) { |
| 210 | trace_rmnet_map_flush_packet_queue(skb, agg_count); |
| 211 | rc = dev_queue_xmit(skb); |
| 212 | rmnet_stats_queue_xmit(rc, RMNET_STATS_QUEUE_XMIT_AGG_TIMEOUT); |
| 213 | } |
| 214 | kfree(work); |
| 215 | } |
| 216 | |
| 217 | /* rmnet_map_aggregate() - Software aggregates multiple packets. |
| 218 | * @skb: current packet being transmitted |
| 219 | * @config: Physical endpoint configuration of the ingress device |
| 220 | * |
| 221 | * Aggregates multiple SKBs into a single large SKB for transmission. MAP |
| 222 | * protocol is used to separate the packets in the buffer. This function |
| 223 | * consumes the argument SKB and should not be further processed by any other |
| 224 | * function. |
| 225 | */ |
| 226 | void rmnet_map_aggregate(struct sk_buff *skb, |
| 227 | struct rmnet_phys_ep_config *config) { |
| 228 | u8 *dest_buff; |
| 229 | struct agg_work *work; |
| 230 | unsigned long flags; |
| 231 | struct sk_buff *agg_skb; |
| 232 | struct timespec diff, last; |
| 233 | int size, rc, agg_count = 0; |
| 234 | |
| 235 | if (!skb || !config) |
| 236 | return; |
| 237 | size = config->egress_agg_size - skb->len; |
| 238 | |
| 239 | if (size < 2000) { |
| 240 | LOGL("Invalid length %d", size); |
| 241 | return; |
| 242 | } |
| 243 | |
| 244 | new_packet: |
| 245 | spin_lock_irqsave(&config->agg_lock, flags); |
| 246 | |
| 247 | memcpy(&last, &config->agg_last, sizeof(struct timespec)); |
| 248 | getnstimeofday(&config->agg_last); |
| 249 | |
| 250 | if (!config->agg_skb) { |
| 251 | /* Check to see if we should agg first. If the traffic is very |
| 252 | * sparse, don't aggregate. We will need to tune this later |
| 253 | */ |
| 254 | diff = timespec_sub(config->agg_last, last); |
| 255 | |
| 256 | if ((diff.tv_sec > 0) || (diff.tv_nsec > agg_bypass_time)) { |
| 257 | spin_unlock_irqrestore(&config->agg_lock, flags); |
| 258 | LOGL("delta t: %ld.%09lu\tcount: bypass", diff.tv_sec, |
| 259 | diff.tv_nsec); |
| 260 | rmnet_stats_agg_pkts(1); |
| 261 | trace_rmnet_map_aggregate(skb, 0); |
| 262 | rc = dev_queue_xmit(skb); |
| 263 | rmnet_stats_queue_xmit(rc, |
| 264 | RMNET_STATS_QUEUE_XMIT_AGG_SKIP); |
| 265 | return; |
| 266 | } |
| 267 | |
| 268 | config->agg_skb = skb_copy_expand(skb, 0, size, GFP_ATOMIC); |
| 269 | if (!config->agg_skb) { |
| 270 | config->agg_skb = 0; |
| 271 | config->agg_count = 0; |
| 272 | memset(&config->agg_time, 0, sizeof(struct timespec)); |
| 273 | spin_unlock_irqrestore(&config->agg_lock, flags); |
| 274 | rmnet_stats_agg_pkts(1); |
| 275 | trace_rmnet_map_aggregate(skb, 0); |
| 276 | rc = dev_queue_xmit(skb); |
| 277 | rmnet_stats_queue_xmit |
| 278 | (rc, |
| 279 | RMNET_STATS_QUEUE_XMIT_AGG_CPY_EXP_FAIL); |
| 280 | return; |
| 281 | } |
| 282 | config->agg_count = 1; |
| 283 | getnstimeofday(&config->agg_time); |
| 284 | trace_rmnet_start_aggregation(skb); |
| 285 | rmnet_kfree_skb(skb, RMNET_STATS_SKBFREE_AGG_CPY_EXPAND); |
| 286 | goto schedule; |
| 287 | } |
| 288 | diff = timespec_sub(config->agg_last, config->agg_time); |
| 289 | |
| 290 | if (skb->len > (config->egress_agg_size - config->agg_skb->len) || |
| 291 | (config->agg_count >= config->egress_agg_count) || |
| 292 | (diff.tv_sec > 0) || (diff.tv_nsec > agg_time_limit)) { |
| 293 | rmnet_stats_agg_pkts(config->agg_count); |
| 294 | agg_skb = config->agg_skb; |
| 295 | agg_count = config->agg_count; |
| 296 | config->agg_skb = 0; |
| 297 | config->agg_count = 0; |
| 298 | memset(&config->agg_time, 0, sizeof(struct timespec)); |
| 299 | spin_unlock_irqrestore(&config->agg_lock, flags); |
| 300 | LOGL("delta t: %ld.%09lu\tcount: %d", diff.tv_sec, |
| 301 | diff.tv_nsec, agg_count); |
| 302 | trace_rmnet_map_aggregate(skb, agg_count); |
| 303 | rc = dev_queue_xmit(agg_skb); |
| 304 | rmnet_stats_queue_xmit(rc, |
| 305 | RMNET_STATS_QUEUE_XMIT_AGG_FILL_BUFFER); |
| 306 | goto new_packet; |
| 307 | } |
| 308 | |
| 309 | dest_buff = skb_put(config->agg_skb, skb->len); |
| 310 | memcpy(dest_buff, skb->data, skb->len); |
| 311 | config->agg_count++; |
| 312 | rmnet_kfree_skb(skb, RMNET_STATS_SKBFREE_AGG_INTO_BUFF); |
| 313 | |
| 314 | schedule: |
| 315 | if (config->agg_state != RMNET_MAP_TXFER_SCHEDULED) { |
| 316 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
| 317 | if (!work) { |
| 318 | LOGE("Failed to allocate work item for packet %s", |
| 319 | "transfer. DATA PATH LIKELY BROKEN!"); |
| 320 | config->agg_state = RMNET_MAP_AGG_IDLE; |
| 321 | spin_unlock_irqrestore(&config->agg_lock, flags); |
| 322 | return; |
| 323 | } |
| 324 | INIT_DELAYED_WORK((struct delayed_work *)work, |
| 325 | rmnet_map_flush_packet_queue); |
| 326 | work->config = config; |
| 327 | config->agg_state = RMNET_MAP_TXFER_SCHEDULED; |
| 328 | schedule_delayed_work((struct delayed_work *)work, 1); |
| 329 | } |
| 330 | spin_unlock_irqrestore(&config->agg_lock, flags); |
| 331 | } |
| 332 | |
| 333 | /* Checksum Offload */ |
| 334 | |
| 335 | static inline u16 *rmnet_map_get_checksum_field(unsigned char protocol, |
| 336 | const void *txporthdr) |
| 337 | { |
| 338 | u16 *check = 0; |
| 339 | |
| 340 | switch (protocol) { |
| 341 | case IPPROTO_TCP: |
| 342 | check = &(((struct tcphdr *)txporthdr)->check); |
| 343 | break; |
| 344 | |
| 345 | case IPPROTO_UDP: |
| 346 | check = &(((struct udphdr *)txporthdr)->check); |
| 347 | break; |
| 348 | |
| 349 | default: |
| 350 | check = 0; |
| 351 | break; |
| 352 | } |
| 353 | |
| 354 | return check; |
| 355 | } |
| 356 | |
| 357 | static inline u16 rmnet_map_add_checksums(u16 val1, u16 val2) |
| 358 | { |
| 359 | int sum = val1 + val2; |
| 360 | |
| 361 | sum = (((sum & 0xFFFF0000) >> 16) + sum) & 0x0000FFFF; |
| 362 | return (u16)(sum & 0x0000FFFF); |
| 363 | } |
| 364 | |
| 365 | static inline u16 rmnet_map_subtract_checksums(u16 val1, u16 val2) |
| 366 | { |
| 367 | return rmnet_map_add_checksums(val1, ~val2); |
| 368 | } |
| 369 | |
| 370 | /* rmnet_map_validate_ipv4_packet_checksum() - Validates TCP/UDP checksum |
| 371 | * value for IPv4 packet |
| 372 | * @map_payload: Pointer to the beginning of the map payload |
| 373 | * @cksum_trailer: Pointer to the checksum trailer |
| 374 | * |
| 375 | * Validates the TCP/UDP checksum for the packet using the checksum value |
| 376 | * from the checksum trailer added to the packet. |
| 377 | * The validation formula is the following: |
| 378 | * 1. Performs 1's complement over the checksum value from the trailer |
| 379 | * 2. Computes 1's complement checksum over IPv4 header and subtracts it from |
| 380 | * the value from step 1 |
| 381 | * 3. Computes 1's complement checksum over IPv4 pseudo header and adds it to |
| 382 | * the value from step 2 |
| 383 | * 4. Subtracts the checksum value from the TCP/UDP header from the value from |
| 384 | * step 3 |
| 385 | * 5. Compares the value from step 4 to the checksum value from the TCP/UDP |
| 386 | * header |
| 387 | * |
| 388 | * Fragmentation and tunneling are not supported. |
| 389 | * |
| 390 | * Return: 0 is validation succeeded. |
| 391 | */ |
| 392 | static int rmnet_map_validate_ipv4_packet_checksum |
| 393 | (unsigned char *map_payload, |
| 394 | struct rmnet_map_dl_checksum_trailer_s *cksum_trailer) |
| 395 | { |
| 396 | struct iphdr *ip4h; |
| 397 | u16 *checksum_field; |
| 398 | void *txporthdr; |
| 399 | u16 pseudo_checksum; |
| 400 | u16 ip_hdr_checksum; |
| 401 | u16 checksum_value; |
| 402 | u16 ip_payload_checksum; |
| 403 | u16 ip_pseudo_payload_checksum; |
| 404 | u16 checksum_value_final; |
| 405 | |
| 406 | ip4h = (struct iphdr *)map_payload; |
| 407 | if ((ntohs(ip4h->frag_off) & IP_MF) || |
| 408 | ((ntohs(ip4h->frag_off) & IP_OFFSET) > 0)) |
| 409 | return RMNET_MAP_CHECKSUM_FRAGMENTED_PACKET; |
| 410 | |
| 411 | txporthdr = map_payload + ip4h->ihl * 4; |
| 412 | |
| 413 | checksum_field = rmnet_map_get_checksum_field(ip4h->protocol, |
| 414 | txporthdr); |
| 415 | |
| 416 | if (unlikely(!checksum_field)) |
| 417 | return RMNET_MAP_CHECKSUM_ERR_UNKNOWN_TRANSPORT; |
| 418 | |
| 419 | /* RFC 768 - Skip IPv4 UDP packets where sender checksum field is 0 */ |
| 420 | if ((*checksum_field == 0) && (ip4h->protocol == IPPROTO_UDP)) |
| 421 | return RMNET_MAP_CHECKSUM_SKIPPED; |
| 422 | |
| 423 | checksum_value = ~ntohs(cksum_trailer->checksum_value); |
| 424 | ip_hdr_checksum = ~ip_fast_csum(ip4h, (int)ip4h->ihl); |
| 425 | ip_payload_checksum = rmnet_map_subtract_checksums(checksum_value, |
| 426 | ip_hdr_checksum); |
| 427 | |
| 428 | pseudo_checksum = ~ntohs(csum_tcpudp_magic(ip4h->saddr, ip4h->daddr, |
| 429 | (u16)(ntohs(ip4h->tot_len) - ip4h->ihl * 4), |
| 430 | (u16)ip4h->protocol, 0)); |
| 431 | ip_pseudo_payload_checksum = rmnet_map_add_checksums( |
| 432 | ip_payload_checksum, pseudo_checksum); |
| 433 | |
| 434 | checksum_value_final = ~rmnet_map_subtract_checksums( |
| 435 | ip_pseudo_payload_checksum, ntohs(*checksum_field)); |
| 436 | |
| 437 | if (unlikely(checksum_value_final == 0)) { |
| 438 | switch (ip4h->protocol) { |
| 439 | case IPPROTO_UDP: |
| 440 | /* RFC 768 */ |
| 441 | LOGD("DL4 1's complement rule for UDP checksum 0"); |
| 442 | checksum_value_final = ~checksum_value_final; |
| 443 | break; |
| 444 | |
| 445 | case IPPROTO_TCP: |
| 446 | if (*checksum_field == 0xFFFF) { |
| 447 | LOGD( |
| 448 | "DL4 Non-RFC compliant TCP checksum found"); |
| 449 | checksum_value_final = ~checksum_value_final; |
| 450 | } |
| 451 | break; |
| 452 | } |
| 453 | } |
| 454 | |
| 455 | LOGD( |
| 456 | "DL4 cksum: ~HW: %04X, field: %04X, pseudo header: %04X, final: %04X", |
| 457 | ~ntohs(cksum_trailer->checksum_value), ntohs(*checksum_field), |
| 458 | pseudo_checksum, checksum_value_final); |
| 459 | |
| 460 | if (checksum_value_final == ntohs(*checksum_field)) |
| 461 | return RMNET_MAP_CHECKSUM_OK; |
| 462 | else |
| 463 | return RMNET_MAP_CHECKSUM_VALIDATION_FAILED; |
| 464 | } |
| 465 | |
| 466 | /* rmnet_map_validate_ipv6_packet_checksum() - Validates TCP/UDP checksum |
| 467 | * value for IPv6 packet |
| 468 | * @map_payload: Pointer to the beginning of the map payload |
| 469 | * @cksum_trailer: Pointer to the checksum trailer |
| 470 | * |
| 471 | * Validates the TCP/UDP checksum for the packet using the checksum value |
| 472 | * from the checksum trailer added to the packet. |
| 473 | * The validation formula is the following: |
| 474 | * 1. Performs 1's complement over the checksum value from the trailer |
| 475 | * 2. Computes 1's complement checksum over IPv6 header and subtracts it from |
| 476 | * the value from step 1 |
| 477 | * 3. Computes 1's complement checksum over IPv6 pseudo header and adds it to |
| 478 | * the value from step 2 |
| 479 | * 4. Subtracts the checksum value from the TCP/UDP header from the value from |
| 480 | * step 3 |
| 481 | * 5. Compares the value from step 4 to the checksum value from the TCP/UDP |
| 482 | * header |
| 483 | * |
| 484 | * Fragmentation, extension headers and tunneling are not supported. |
| 485 | * |
| 486 | * Return: 0 is validation succeeded. |
| 487 | */ |
| 488 | static int rmnet_map_validate_ipv6_packet_checksum |
| 489 | (unsigned char *map_payload, |
| 490 | struct rmnet_map_dl_checksum_trailer_s *cksum_trailer) |
| 491 | { |
| 492 | struct ipv6hdr *ip6h; |
| 493 | u16 *checksum_field; |
| 494 | void *txporthdr; |
| 495 | u16 pseudo_checksum; |
| 496 | u16 ip_hdr_checksum; |
| 497 | u16 checksum_value; |
| 498 | u16 ip_payload_checksum; |
| 499 | u16 ip_pseudo_payload_checksum; |
| 500 | u16 checksum_value_final; |
| 501 | u32 length; |
| 502 | |
| 503 | ip6h = (struct ipv6hdr *)map_payload; |
| 504 | |
| 505 | txporthdr = map_payload + sizeof(struct ipv6hdr); |
| 506 | checksum_field = rmnet_map_get_checksum_field(ip6h->nexthdr, |
| 507 | txporthdr); |
| 508 | |
| 509 | if (unlikely(!checksum_field)) |
| 510 | return RMNET_MAP_CHECKSUM_ERR_UNKNOWN_TRANSPORT; |
| 511 | |
| 512 | checksum_value = ~ntohs(cksum_trailer->checksum_value); |
| 513 | ip_hdr_checksum = ~ntohs(ip_compute_csum(ip6h, |
| 514 | (int)(txporthdr - (void *)map_payload))); |
| 515 | ip_payload_checksum = rmnet_map_subtract_checksums |
| 516 | (checksum_value, ip_hdr_checksum); |
| 517 | |
| 518 | length = (ip6h->nexthdr == IPPROTO_UDP) ? |
| 519 | ntohs(((struct udphdr *)txporthdr)->len) : |
| 520 | ntohs(ip6h->payload_len); |
| 521 | pseudo_checksum = ~ntohs(csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, |
| 522 | length, ip6h->nexthdr, 0)); |
| 523 | ip_pseudo_payload_checksum = rmnet_map_add_checksums( |
| 524 | ip_payload_checksum, pseudo_checksum); |
| 525 | |
| 526 | checksum_value_final = ~rmnet_map_subtract_checksums( |
| 527 | ip_pseudo_payload_checksum, ntohs(*checksum_field)); |
| 528 | |
| 529 | if (unlikely(checksum_value_final == 0)) { |
| 530 | switch (ip6h->nexthdr) { |
| 531 | case IPPROTO_UDP: |
| 532 | /* RFC 2460 section 8.1 */ |
| 533 | LOGD("DL6 One's complement rule for UDP checksum 0"); |
| 534 | checksum_value_final = ~checksum_value_final; |
| 535 | break; |
| 536 | |
| 537 | case IPPROTO_TCP: |
| 538 | if (*checksum_field == 0xFFFF) { |
| 539 | LOGD( |
| 540 | "DL6 Non-RFC compliant TCP checksum found"); |
| 541 | checksum_value_final = ~checksum_value_final; |
| 542 | } |
| 543 | break; |
| 544 | } |
| 545 | } |
| 546 | |
| 547 | LOGD( |
| 548 | "DL6 cksum: ~HW: %04X, field: %04X, pseudo header: %04X, final: %04X", |
| 549 | ~ntohs(cksum_trailer->checksum_value), ntohs(*checksum_field), |
| 550 | pseudo_checksum, checksum_value_final); |
| 551 | |
| 552 | if (checksum_value_final == ntohs(*checksum_field)) |
| 553 | return RMNET_MAP_CHECKSUM_OK; |
| 554 | else |
| 555 | return RMNET_MAP_CHECKSUM_VALIDATION_FAILED; |
| 556 | } |
| 557 | |
| 558 | /* rmnet_map_checksum_downlink_packet() - Validates checksum on |
| 559 | * a downlink packet |
| 560 | * @skb: Pointer to the packet's skb. |
| 561 | * |
| 562 | * Validates packet checksums. Function takes a pointer to |
| 563 | * the beginning of a buffer which contains the entire MAP |
| 564 | * frame: MAP header + IP payload + padding + checksum trailer. |
| 565 | * Currently, only IPv4 and IPv6 are supported along with |
| 566 | * TCP & UDP. Fragmented or tunneled packets are not supported. |
| 567 | * |
| 568 | * Return: |
| 569 | * - RMNET_MAP_CHECKSUM_OK: Validation of checksum succeeded. |
| 570 | * - RMNET_MAP_CHECKSUM_ERR_BAD_BUFFER: Skb buffer given is corrupted. |
| 571 | * - RMNET_MAP_CHECKSUM_VALID_FLAG_NOT_SET: Valid flag is not set in the |
| 572 | * checksum trailer. |
| 573 | * - RMNET_MAP_CHECKSUM_FRAGMENTED_PACKET: The packet is a fragment. |
| 574 | * - RMNET_MAP_CHECKSUM_ERR_UNKNOWN_TRANSPORT: The transport header is |
| 575 | * not TCP/UDP. |
| 576 | * - RMNET_MAP_CHECKSUM_ERR_UNKNOWN_IP_VERSION: Unrecognized IP header. |
| 577 | * - RMNET_MAP_CHECKSUM_VALIDATION_FAILED: In case the validation failed. |
| 578 | */ |
| 579 | int rmnet_map_checksum_downlink_packet(struct sk_buff *skb) |
| 580 | { |
| 581 | struct rmnet_map_dl_checksum_trailer_s *cksum_trailer; |
| 582 | unsigned int data_len; |
| 583 | unsigned char *map_payload; |
| 584 | unsigned char ip_version; |
| 585 | |
| 586 | data_len = RMNET_MAP_GET_LENGTH(skb); |
| 587 | |
| 588 | if (unlikely(skb->len < (sizeof(struct rmnet_map_header_s) + data_len + |
| 589 | sizeof(struct rmnet_map_dl_checksum_trailer_s)))) |
| 590 | return RMNET_MAP_CHECKSUM_ERR_BAD_BUFFER; |
| 591 | |
| 592 | cksum_trailer = (struct rmnet_map_dl_checksum_trailer_s *) |
| 593 | (skb->data + data_len |
| 594 | + sizeof(struct rmnet_map_header_s)); |
| 595 | |
| 596 | if (unlikely(!ntohs(cksum_trailer->valid))) |
| 597 | return RMNET_MAP_CHECKSUM_VALID_FLAG_NOT_SET; |
| 598 | |
| 599 | map_payload = (unsigned char *)(skb->data |
| 600 | + sizeof(struct rmnet_map_header_s)); |
| 601 | |
| 602 | ip_version = (*map_payload & 0xF0) >> 4; |
| 603 | if (ip_version == 0x04) |
| 604 | return rmnet_map_validate_ipv4_packet_checksum(map_payload, |
| 605 | cksum_trailer); |
| 606 | else if (ip_version == 0x06) |
| 607 | return rmnet_map_validate_ipv6_packet_checksum(map_payload, |
| 608 | cksum_trailer); |
| 609 | |
| 610 | return RMNET_MAP_CHECKSUM_ERR_UNKNOWN_IP_VERSION; |
| 611 | } |
| 612 | |
| 613 | static void rmnet_map_fill_ipv4_packet_ul_checksum_header |
| 614 | (void *iphdr, struct rmnet_map_ul_checksum_header_s *ul_header, |
| 615 | struct sk_buff *skb) |
| 616 | { |
| 617 | struct iphdr *ip4h = (struct iphdr *)iphdr; |
| 618 | unsigned short *hdr = (unsigned short *)ul_header; |
| 619 | |
| 620 | ul_header->checksum_start_offset = htons((unsigned short) |
| 621 | (skb_transport_header(skb) - (unsigned char *)iphdr)); |
| 622 | ul_header->checksum_insert_offset = skb->csum_offset; |
| 623 | ul_header->cks_en = 1; |
| 624 | if (ip4h->protocol == IPPROTO_UDP) |
| 625 | ul_header->udp_ip4_ind = 1; |
| 626 | else |
| 627 | ul_header->udp_ip4_ind = 0; |
| 628 | /* Changing checksum_insert_offset to network order */ |
| 629 | hdr++; |
| 630 | *hdr = htons(*hdr); |
| 631 | skb->ip_summed = CHECKSUM_NONE; |
| 632 | } |
| 633 | |
| 634 | static void rmnet_map_fill_ipv6_packet_ul_checksum_header |
| 635 | (void *iphdr, struct rmnet_map_ul_checksum_header_s *ul_header, |
| 636 | struct sk_buff *skb) |
| 637 | { |
| 638 | unsigned short *hdr = (unsigned short *)ul_header; |
| 639 | |
| 640 | ul_header->checksum_start_offset = htons((unsigned short) |
| 641 | (skb_transport_header(skb) - (unsigned char *)iphdr)); |
| 642 | ul_header->checksum_insert_offset = skb->csum_offset; |
| 643 | ul_header->cks_en = 1; |
| 644 | ul_header->udp_ip4_ind = 0; |
| 645 | /* Changing checksum_insert_offset to network order */ |
| 646 | hdr++; |
| 647 | *hdr = htons(*hdr); |
| 648 | skb->ip_summed = CHECKSUM_NONE; |
| 649 | } |
| 650 | |
| 651 | static void rmnet_map_complement_ipv4_txporthdr_csum_field(void *iphdr) |
| 652 | { |
| 653 | struct iphdr *ip4h = (struct iphdr *)iphdr; |
| 654 | void *txporthdr; |
| 655 | u16 *csum; |
| 656 | |
| 657 | txporthdr = iphdr + ip4h->ihl * 4; |
| 658 | |
| 659 | if ((ip4h->protocol == IPPROTO_TCP) || |
| 660 | (ip4h->protocol == IPPROTO_UDP)) { |
| 661 | csum = (u16 *)rmnet_map_get_checksum_field(ip4h->protocol, |
| 662 | txporthdr); |
| 663 | *csum = ~(*csum); |
| 664 | } |
| 665 | } |
| 666 | |
| 667 | static void rmnet_map_complement_ipv6_txporthdr_csum_field(void *ip6hdr) |
| 668 | { |
| 669 | struct ipv6hdr *ip6h = (struct ipv6hdr *)ip6hdr; |
| 670 | void *txporthdr; |
| 671 | u16 *csum; |
| 672 | |
| 673 | txporthdr = ip6hdr + sizeof(struct ipv6hdr); |
| 674 | |
| 675 | if ((ip6h->nexthdr == IPPROTO_TCP) || (ip6h->nexthdr == IPPROTO_UDP)) { |
| 676 | csum = (u16 *)rmnet_map_get_checksum_field(ip6h->nexthdr, |
| 677 | txporthdr); |
| 678 | *csum = ~(*csum); |
| 679 | } |
| 680 | } |
| 681 | |
| 682 | /* rmnet_map_checksum_uplink_packet() - Generates UL checksum |
| 683 | * meta info header |
| 684 | * @skb: Pointer to the packet's skb. |
| 685 | * |
| 686 | * Generates UL checksum meta info header for IPv4 and IPv6 over TCP and UDP |
| 687 | * packets that are supported for UL checksum offload. |
| 688 | * |
| 689 | * Return: |
| 690 | * - RMNET_MAP_CHECKSUM_OK: Validation of checksum succeeded. |
| 691 | * - RMNET_MAP_CHECKSUM_ERR_UNKNOWN_IP_VERSION: Unrecognized IP header. |
| 692 | * - RMNET_MAP_CHECKSUM_SW: Unsupported packet for UL checksum offload. |
| 693 | */ |
| 694 | int rmnet_map_checksum_uplink_packet(struct sk_buff *skb, |
| 695 | struct net_device *orig_dev, |
| 696 | u32 egress_data_format) |
| 697 | { |
| 698 | unsigned char ip_version; |
| 699 | struct rmnet_map_ul_checksum_header_s *ul_header; |
| 700 | void *iphdr; |
| 701 | int ret; |
| 702 | |
| 703 | ul_header = (struct rmnet_map_ul_checksum_header_s *) |
| 704 | skb_push(skb, sizeof(struct rmnet_map_ul_checksum_header_s)); |
| 705 | |
| 706 | if (unlikely(!(orig_dev->features & |
| 707 | (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM)))) { |
| 708 | ret = RMNET_MAP_CHECKSUM_SW; |
| 709 | goto sw_checksum; |
| 710 | } |
| 711 | |
| 712 | if (skb->ip_summed == CHECKSUM_PARTIAL) { |
| 713 | iphdr = (char *)ul_header + |
| 714 | sizeof(struct rmnet_map_ul_checksum_header_s); |
| 715 | ip_version = (*(char *)iphdr & 0xF0) >> 4; |
| 716 | if (ip_version == 0x04) { |
| 717 | rmnet_map_fill_ipv4_packet_ul_checksum_header |
| 718 | (iphdr, ul_header, skb); |
| 719 | if (egress_data_format & |
| 720 | RMNET_EGRESS_FORMAT_MAP_CKSUMV4) |
| 721 | rmnet_map_complement_ipv4_txporthdr_csum_field( |
| 722 | iphdr); |
| 723 | ret = RMNET_MAP_CHECKSUM_OK; |
| 724 | goto done; |
| 725 | } else if (ip_version == 0x06) { |
| 726 | rmnet_map_fill_ipv6_packet_ul_checksum_header |
| 727 | (iphdr, ul_header, skb); |
| 728 | if (egress_data_format & |
| 729 | RMNET_EGRESS_FORMAT_MAP_CKSUMV4) |
| 730 | rmnet_map_complement_ipv6_txporthdr_csum_field( |
| 731 | iphdr); |
| 732 | ret = RMNET_MAP_CHECKSUM_OK; |
| 733 | goto done; |
| 734 | } else { |
| 735 | ret = RMNET_MAP_CHECKSUM_ERR_UNKNOWN_IP_VERSION; |
| 736 | goto sw_checksum; |
| 737 | } |
| 738 | } else { |
| 739 | ret = RMNET_MAP_CHECKSUM_SW; |
| 740 | goto sw_checksum; |
| 741 | } |
| 742 | |
| 743 | sw_checksum: |
| 744 | ul_header->checksum_start_offset = 0; |
| 745 | ul_header->checksum_insert_offset = 0; |
| 746 | ul_header->cks_en = 0; |
| 747 | ul_header->udp_ip4_ind = 0; |
| 748 | done: |
| 749 | return ret; |
| 750 | } |