1 /* 2 * Copyright (C) 2011-2014 Universita` di Pisa. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 /* 28 * $FreeBSD$ 29 * 30 * Functions and macros to manipulate netmap structures and packets 31 * in userspace. See netmap(4) for more information. 32 * 33 * The address of the struct netmap_if, say nifp, is computed from the 34 * value returned from ioctl(.., NIOCREG, ...) and the mmap region: 35 * ioctl(fd, NIOCREG, &req); 36 * mem = mmap(0, ... ); 37 * nifp = NETMAP_IF(mem, req.nr_nifp); 38 * (so simple, we could just do it manually) 39 * 40 * From there: 41 * struct netmap_ring *NETMAP_TXRING(nifp, index) 42 * struct netmap_ring *NETMAP_RXRING(nifp, index) 43 * we can access ring->cur, ring->head, ring->tail, etc. 44 * 45 * ring->slot[i] gives us the i-th slot (we can access 46 * directly len, flags, buf_idx) 47 * 48 * char *buf = NETMAP_BUF(ring, x) returns a pointer to 49 * the buffer numbered x 50 * 51 * All ring indexes (head, cur, tail) should always move forward. 52 * To compute the next index in a circular ring you can use 53 * i = nm_ring_next(ring, i); 54 * 55 * To ease porting apps from pcap to netmap we supply a few fuctions 56 * that can be called to open, close, read and write on netmap in a way 57 * similar to libpcap. Note that the read/write function depend on 58 * an ioctl()/select()/poll() being issued to refill rings or push 59 * packets out. 60 * 61 * In order to use these, include #define NETMAP_WITH_LIBS 62 * in the source file that invokes these functions. 63 */ 64 65 #ifndef _NET_NETMAP_USER_H_ 66 #define _NET_NETMAP_USER_H_ 67 68 #include <stdint.h> 69 #include <sys/socket.h> /* apple needs sockaddr */ 70 #include <net/if.h> /* IFNAMSIZ */ 71 72 #ifndef likely 73 #define likely(x) __builtin_expect(!!(x), 1) 74 #define unlikely(x) __builtin_expect(!!(x), 0) 75 #endif /* likely and unlikely */ 76 77 #include <net/netmap.h> 78 79 /* helper macro */ 80 #define _NETMAP_OFFSET(type, ptr, offset) \ 81 ((type)(void *)((char *)(ptr) + (offset))) 82 83 #define NETMAP_IF(_base, _ofs) _NETMAP_OFFSET(struct netmap_if *, _base, _ofs) 84 85 #define NETMAP_TXRING(nifp, index) _NETMAP_OFFSET(struct netmap_ring *, \ 86 nifp, (nifp)->ring_ofs[index] ) 87 88 #define NETMAP_RXRING(nifp, index) _NETMAP_OFFSET(struct netmap_ring *, \ 89 nifp, (nifp)->ring_ofs[index + (nifp)->ni_tx_rings + 1] ) 90 91 #define NETMAP_BUF(ring, index) \ 92 ((char *)(ring) + (ring)->buf_ofs + ((index)*(ring)->nr_buf_size)) 93 94 #define NETMAP_BUF_IDX(ring, buf) \ 95 ( ((char *)(buf) - ((char *)(ring) + (ring)->buf_ofs) ) / \ 96 (ring)->nr_buf_size ) 97 98 99 static inline uint32_t 100 nm_ring_next(struct netmap_ring *r, uint32_t i) 101 { 102 return ( unlikely(i + 1 == r->num_slots) ? 0 : i + 1); 103 } 104 105 106 /* 107 * Return 1 if we have pending transmissions in the tx ring. 108 * When everything is complete ring->head = ring->tail + 1 (modulo ring size) 109 */ 110 static inline int 111 nm_tx_pending(struct netmap_ring *r) 112 { 113 return nm_ring_next(r, r->tail) != r->head; 114 } 115 116 117 static inline uint32_t 118 nm_ring_space(struct netmap_ring *ring) 119 { 120 int ret = ring->tail - ring->cur; 121 if (ret < 0) 122 ret += ring->num_slots; 123 return ret; 124 } 125 126 127 #ifdef NETMAP_WITH_LIBS 128 /* 129 * Support for simple I/O libraries. 130 * Include other system headers required for compiling this. 131 */ 132 133 #ifndef HAVE_NETMAP_WITH_LIBS 134 #define HAVE_NETMAP_WITH_LIBS 135 136 #include <stdio.h> 137 #include <sys/time.h> 138 #include <sys/mman.h> 139 #include <string.h> /* memset */ 140 #include <sys/ioctl.h> 141 #include <sys/errno.h> /* EINVAL */ 142 #include <fcntl.h> /* O_RDWR */ 143 #include <unistd.h> /* close() */ 144 #include <signal.h> 145 #include <stdlib.h> 146 147 #ifndef ND /* debug macros */ 148 /* debug support */ 149 #define ND(_fmt, ...) do {} while(0) 150 #define D(_fmt, ...) \ 151 do { \ 152 struct timeval _t0; \ 153 gettimeofday(&_t0, NULL); \ 154 fprintf(stderr, "%03d.%06d %s [%d] " _fmt "\n", \ 155 (int)(_t0.tv_sec % 1000), (int)_t0.tv_usec, \ 156 __FUNCTION__, __LINE__, ##__VA_ARGS__); \ 157 } while (0) 158 159 /* Rate limited version of "D", lps indicates how many per second */ 160 #define RD(lps, format, ...) \ 161 do { \ 162 static int __t0, __cnt; \ 163 struct timeval __xxts; \ 164 gettimeofday(&__xxts, NULL); \ 165 if (__t0 != __xxts.tv_sec) { \ 166 __t0 = __xxts.tv_sec; \ 167 __cnt = 0; \ 168 } \ 169 if (__cnt++ < lps) { \ 170 D(format, ##__VA_ARGS__); \ 171 } \ 172 } while (0) 173 #endif 174 175 struct nm_pkthdr { /* same as pcap_pkthdr */ 176 struct timeval ts; 177 uint32_t caplen; 178 uint32_t len; 179 }; 180 181 struct nm_stat { /* same as pcap_stat */ 182 u_int ps_recv; 183 u_int ps_drop; 184 u_int ps_ifdrop; 185 #ifdef WIN32 186 u_int bs_capt; 187 #endif /* WIN32 */ 188 }; 189 190 #define NM_ERRBUF_SIZE 512 191 192 struct nm_desc { 193 struct nm_desc *self; /* point to self if netmap. */ 194 int fd; 195 void *mem; 196 uint32_t memsize; 197 int done_mmap; /* set if mem is the result of mmap */ 198 struct netmap_if * const nifp; 199 uint16_t first_tx_ring, last_tx_ring, cur_tx_ring; 200 uint16_t first_rx_ring, last_rx_ring, cur_rx_ring; 201 struct nmreq req; /* also contains the nr_name = ifname */ 202 struct nm_pkthdr hdr; 203 204 /* 205 * The memory contains netmap_if, rings and then buffers. 206 * Given a pointer (e.g. to nm_inject) we can compare with 207 * mem/buf_start/buf_end to tell if it is a buffer or 208 * some other descriptor in our region. 209 * We also store a pointer to some ring as it helps in the 210 * translation from buffer indexes to addresses. 211 */ 212 struct netmap_ring * const some_ring; 213 void * const buf_start; 214 void * const buf_end; 215 /* parameters from pcap_open_live */ 216 int snaplen; 217 int promisc; 218 int to_ms; 219 char *errbuf; 220 221 /* save flags so we can restore them on close */ 222 uint32_t if_flags; 223 uint32_t if_reqcap; 224 uint32_t if_curcap; 225 226 struct nm_stat st; 227 char msg[NM_ERRBUF_SIZE]; 228 }; 229 230 /* 231 * when the descriptor is open correctly, d->self == d 232 * Eventually we should also use some magic number. 233 */ 234 #define P2NMD(p) ((struct nm_desc *)(p)) 235 #define IS_NETMAP_DESC(d) ((d) && P2NMD(d)->self == P2NMD(d)) 236 #define NETMAP_FD(d) (P2NMD(d)->fd) 237 238 239 /* 240 * this is a slightly optimized copy routine which rounds 241 * to multiple of 64 bytes and is often faster than dealing 242 * with other odd sizes. We assume there is enough room 243 * in the source and destination buffers. 244 * 245 * XXX only for multiples of 64 bytes, non overlapped. 246 */ 247 static inline void 248 nm_pkt_copy(const void *_src, void *_dst, int l) 249 { 250 const uint64_t *src = (const uint64_t *)_src; 251 uint64_t *dst = (uint64_t *)_dst; 252 253 if (unlikely(l >= 1024)) { 254 memcpy(dst, src, l); 255 return; 256 } 257 for (; likely(l > 0); l-=64) { 258 *dst++ = *src++; 259 *dst++ = *src++; 260 *dst++ = *src++; 261 *dst++ = *src++; 262 *dst++ = *src++; 263 *dst++ = *src++; 264 *dst++ = *src++; 265 *dst++ = *src++; 266 } 267 } 268 269 270 /* 271 * The callback, invoked on each received packet. Same as libpcap 272 */ 273 typedef void (*nm_cb_t)(u_char *, const struct nm_pkthdr *, const u_char *d); 274 275 /* 276 *--- the pcap-like API --- 277 * 278 * nm_open() opens a file descriptor, binds to a port and maps memory. 279 * 280 * ifname (netmap:foo or vale:foo) is the port name 281 * a suffix can indicate the follwing: 282 * ^ bind the host (sw) ring pair 283 * * bind host and NIC ring pairs (transparent) 284 * -NN bind individual NIC ring pair 285 * {NN bind master side of pipe NN 286 * }NN bind slave side of pipe NN 287 * 288 * req provides the initial values of nmreq before parsing ifname. 289 * Remember that the ifname parsing will override the ring 290 * number in nm_ringid, and part of nm_flags; 291 * flags special functions, normally 0 292 * indicates which fields of *arg are significant 293 * arg special functions, normally NULL 294 * if passed a netmap_desc with mem != NULL, 295 * use that memory instead of mmap. 296 */ 297 298 static struct nm_desc *nm_open(const char *ifname, const struct nmreq *req, 299 uint64_t flags, const struct nm_desc *arg); 300 301 /* 302 * nm_open can import some fields from the parent descriptor. 303 * These flags control which ones. 304 * Also in flags you can specify NETMAP_NO_TX_POLL and NETMAP_DO_RX_POLL, 305 * which set the initial value for these flags. 306 * Note that the 16 low bits of the flags are reserved for data 307 * that may go into the nmreq. 308 */ 309 enum { 310 NM_OPEN_NO_MMAP = 0x040000, /* reuse mmap from parent */ 311 NM_OPEN_IFNAME = 0x080000, /* nr_name, nr_ringid, nr_flags */ 312 NM_OPEN_ARG1 = 0x100000, 313 NM_OPEN_ARG2 = 0x200000, 314 NM_OPEN_ARG3 = 0x400000, 315 NM_OPEN_RING_CFG = 0x800000, /* tx|rx rings|slots */ 316 }; 317 318 319 /* 320 * nm_close() closes and restores the port to its previous state 321 */ 322 323 static int nm_close(struct nm_desc *); 324 325 /* 326 * nm_inject() is the same as pcap_inject() 327 * nm_dispatch() is the same as pcap_dispatch() 328 * nm_nextpkt() is the same as pcap_next() 329 */ 330 331 static int nm_inject(struct nm_desc *, const void *, size_t); 332 static int nm_dispatch(struct nm_desc *, int, nm_cb_t, u_char *); 333 static u_char *nm_nextpkt(struct nm_desc *, struct nm_pkthdr *); 334 335 336 /* 337 * Try to open, return descriptor if successful, NULL otherwise. 338 * An invalid netmap name will return errno = 0; 339 * You can pass a pointer to a pre-filled nm_desc to add special 340 * parameters. Flags is used as follows 341 * NM_OPEN_NO_MMAP use the memory from arg, only 342 * if the nr_arg2 (memory block) matches. 343 * NM_OPEN_ARG1 use req.nr_arg1 from arg 344 * NM_OPEN_ARG2 use req.nr_arg2 from arg 345 * NM_OPEN_RING_CFG user ring config from arg 346 */ 347 static struct nm_desc * 348 nm_open(const char *ifname, const struct nmreq *req, 349 uint64_t new_flags, const struct nm_desc *arg) 350 { 351 struct nm_desc *d = NULL; 352 const struct nm_desc *parent = arg; 353 u_int namelen; 354 uint32_t nr_ringid = 0, nr_flags; 355 const char *port = NULL; 356 const char *errmsg = NULL; 357 358 if (strncmp(ifname, "netmap:", 7) && strncmp(ifname, "vale", 4)) { 359 errno = 0; /* name not recognised, not an error */ 360 return NULL; 361 } 362 if (ifname[0] == 'n') 363 ifname += 7; 364 /* scan for a separator */ 365 for (port = ifname; *port && !index("-*^{}", *port); port++) 366 ; 367 namelen = port - ifname; 368 if (namelen >= sizeof(d->req.nr_name)) { 369 errmsg = "name too long"; 370 goto fail; 371 } 372 switch (*port) { 373 default: /* '\0', no suffix */ 374 nr_flags = NR_REG_ALL_NIC; 375 break; 376 case '-': /* one NIC */ 377 nr_flags = NR_REG_ONE_NIC; 378 nr_ringid = atoi(port + 1); 379 break; 380 case '*': /* NIC and SW, ignore port */ 381 nr_flags = NR_REG_NIC_SW; 382 if (port[1]) { 383 errmsg = "invalid port for nic+sw"; 384 goto fail; 385 } 386 break; 387 case '^': /* only sw ring */ 388 nr_flags = NR_REG_SW; 389 if (port[1]) { 390 errmsg = "invalid port for sw ring"; 391 goto fail; 392 } 393 break; 394 case '{': 395 nr_flags = NR_REG_PIPE_MASTER; 396 nr_ringid = atoi(port + 1); 397 break; 398 case '}': 399 nr_flags = NR_REG_PIPE_SLAVE; 400 nr_ringid = atoi(port + 1); 401 break; 402 } 403 404 if (nr_ringid >= NETMAP_RING_MASK) { 405 errmsg = "invalid ringid"; 406 goto fail; 407 } 408 409 d = (struct nm_desc *)calloc(1, sizeof(*d)); 410 if (d == NULL) { 411 errmsg = "nm_desc alloc failure"; 412 errno = ENOMEM; 413 return NULL; 414 } 415 d->self = d; /* set this early so nm_close() works */ 416 d->fd = open("/dev/netmap", O_RDWR); 417 if (d->fd < 0) { 418 errmsg = "cannot open /dev/netmap"; 419 goto fail; 420 } 421 422 if (req) 423 d->req = *req; 424 d->req.nr_version = NETMAP_API; 425 d->req.nr_ringid &= ~NETMAP_RING_MASK; 426 427 /* these fields are overridden by ifname and flags processing */ 428 d->req.nr_ringid |= nr_ringid; 429 d->req.nr_flags = nr_flags; 430 memcpy(d->req.nr_name, ifname, namelen); 431 d->req.nr_name[namelen] = '\0'; 432 /* optionally import info from parent */ 433 if (IS_NETMAP_DESC(parent) && new_flags) { 434 if (new_flags & NM_OPEN_ARG1) 435 D("overriding ARG1 %d", parent->req.nr_arg1); 436 d->req.nr_arg1 = new_flags & NM_OPEN_ARG1 ? 437 parent->req.nr_arg1 : 4; 438 if (new_flags & NM_OPEN_ARG2) 439 D("overriding ARG2 %d", parent->req.nr_arg2); 440 d->req.nr_arg2 = new_flags & NM_OPEN_ARG2 ? 441 parent->req.nr_arg2 : 0; 442 if (new_flags & NM_OPEN_ARG3) 443 D("overriding ARG3 %d", parent->req.nr_arg3); 444 d->req.nr_arg3 = new_flags & NM_OPEN_ARG3 ? 445 parent->req.nr_arg3 : 0; 446 if (new_flags & NM_OPEN_RING_CFG) { 447 D("overriding RING_CFG"); 448 d->req.nr_tx_slots = parent->req.nr_tx_slots; 449 d->req.nr_rx_slots = parent->req.nr_rx_slots; 450 d->req.nr_tx_rings = parent->req.nr_tx_rings; 451 d->req.nr_rx_rings = parent->req.nr_rx_rings; 452 } 453 if (new_flags & NM_OPEN_IFNAME) { 454 D("overriding ifname %s ringid 0x%x flags 0x%x", 455 parent->req.nr_name, parent->req.nr_ringid, 456 parent->req.nr_flags); 457 memcpy(d->req.nr_name, parent->req.nr_name, 458 sizeof(d->req.nr_name)); 459 d->req.nr_ringid = parent->req.nr_ringid; 460 d->req.nr_flags = parent->req.nr_flags; 461 } 462 } 463 /* add the *XPOLL flags */ 464 d->req.nr_ringid |= new_flags & (NETMAP_NO_TX_POLL | NETMAP_DO_RX_POLL); 465 466 if (ioctl(d->fd, NIOCREGIF, &d->req)) { 467 errmsg = "NIOCREGIF failed"; 468 goto fail; 469 } 470 471 if (IS_NETMAP_DESC(parent) && parent->mem && 472 parent->req.nr_arg2 == d->req.nr_arg2) { 473 /* do not mmap, inherit from parent */ 474 d->memsize = parent->memsize; 475 d->mem = parent->mem; 476 } else { 477 /* XXX TODO: check if memsize is too large (or there is overflow) */ 478 d->memsize = d->req.nr_memsize; 479 d->mem = mmap(0, d->memsize, PROT_WRITE | PROT_READ, MAP_SHARED, 480 d->fd, 0); 481 if (d->mem == MAP_FAILED) { 482 errmsg = "mmap failed"; 483 goto fail; 484 } 485 d->done_mmap = 1; 486 } 487 { 488 struct netmap_if *nifp = NETMAP_IF(d->mem, d->req.nr_offset); 489 struct netmap_ring *r = NETMAP_RXRING(nifp, ); 490 491 *(struct netmap_if **)(uintptr_t)&(d->nifp) = nifp; 492 *(struct netmap_ring **)(uintptr_t)&d->some_ring = r; 493 *(void **)(uintptr_t)&d->buf_start = NETMAP_BUF(r, 0); 494 *(void **)(uintptr_t)&d->buf_end = 495 (char *)d->mem + d->memsize; 496 } 497 498 if (d->req.nr_flags == NR_REG_SW) { /* host stack */ 499 d->first_tx_ring = d->last_tx_ring = d->req.nr_tx_rings; 500 d->first_rx_ring = d->last_rx_ring = d->req.nr_rx_rings; 501 } else if (d->req.nr_flags == NR_REG_ALL_NIC) { /* only nic */ 502 d->first_tx_ring = 0; 503 d->first_rx_ring = 0; 504 d->last_tx_ring = d->req.nr_tx_rings - 1; 505 d->last_rx_ring = d->req.nr_rx_rings - 1; 506 } else if (d->req.nr_flags == NR_REG_NIC_SW) { 507 d->first_tx_ring = 0; 508 d->first_rx_ring = 0; 509 d->last_tx_ring = d->req.nr_tx_rings; 510 d->last_rx_ring = d->req.nr_rx_rings; 511 } else if (d->req.nr_flags == NR_REG_ONE_NIC) { 512 /* XXX check validity */ 513 d->first_tx_ring = d->last_tx_ring = 514 d->first_rx_ring = d->last_rx_ring = d->req.nr_ringid & NETMAP_RING_MASK; 515 } else { /* pipes */ 516 d->first_tx_ring = d->last_tx_ring = 0; 517 d->first_rx_ring = d->last_rx_ring = 0; 518 } 519 520 #ifdef DEBUG_NETMAP_USER 521 { /* debugging code */ 522 int i; 523 524 D("%s tx %d .. %d %d rx %d .. %d %d", ifname, 525 d->first_tx_ring, d->last_tx_ring, d->req.nr_tx_rings, 526 d->first_rx_ring, d->last_rx_ring, d->req.nr_rx_rings); 527 for (i = 0; i <= d->req.nr_tx_rings; i++) { 528 struct netmap_ring *r = NETMAP_TXRING(d->nifp, i); 529 D("TX%d %p h %d c %d t %d", i, r, r->head, r->cur, r->tail); 530 } 531 for (i = 0; i <= d->req.nr_rx_rings; i++) { 532 struct netmap_ring *r = NETMAP_RXRING(d->nifp, i); 533 D("RX%d %p h %d c %d t %d", i, r, r->head, r->cur, r->tail); 534 } 535 } 536 #endif /* debugging */ 537 538 d->cur_tx_ring = d->first_tx_ring; 539 d->cur_rx_ring = d->first_rx_ring; 540 return d; 541 542 fail: 543 nm_close(d); 544 if (errmsg) 545 D("%s %s", errmsg, ifname); 546 if (errno == 0) 547 errno = EINVAL; 548 return NULL; 549 } 550 551 552 static int 553 nm_close(struct nm_desc *d) 554 { 555 /* 556 * ugly trick to avoid unused warnings 557 */ 558 static void *__xxzt[] __attribute__ ((unused)) = 559 { (void *)nm_open, (void *)nm_inject, 560 (void *)nm_dispatch, (void *)nm_nextpkt } ; 561 562 if (d == NULL || d->self != d) 563 return EINVAL; 564 if (d->done_mmap && d->mem) 565 munmap(d->mem, d->memsize); 566 if (d->fd != -1) 567 close(d->fd); 568 bzero(d, sizeof(*d)); 569 free(d); 570 return 0; 571 } 572 573 574 /* 575 * Same prototype as pcap_inject(), only need to cast. 576 */ 577 static int 578 nm_inject(struct nm_desc *d, const void *buf, size_t size) 579 { 580 u_int c, n = d->last_tx_ring - d->first_tx_ring + 1; 581 582 for (c = 0; c < n ; c++) { 583 /* compute current ring to use */ 584 struct netmap_ring *ring; 585 uint32_t i, idx; 586 uint32_t ri = d->cur_tx_ring + c; 587 588 if (ri > d->last_tx_ring) 589 ri = d->first_tx_ring; 590 ring = NETMAP_TXRING(d->nifp, ri); 591 if (nm_ring_empty(ring)) { 592 continue; 593 } 594 i = ring->cur; 595 idx = ring->slot[i].buf_idx; 596 ring->slot[i].len = size; 597 nm_pkt_copy(buf, NETMAP_BUF(ring, idx), size); 598 d->cur_tx_ring = ri; 599 ring->head = ring->cur = nm_ring_next(ring, i); 600 return size; 601 } 602 return 0; /* fail */ 603 } 604 605 606 /* 607 * Same prototype as pcap_dispatch(), only need to cast. 608 */ 609 static int 610 nm_dispatch(struct nm_desc *d, int cnt, nm_cb_t cb, u_char *arg) 611 { 612 int n = d->last_rx_ring - d->first_rx_ring + 1; 613 int c, got = 0, ri = d->cur_rx_ring; 614 615 if (cnt == 0) 616 cnt = -1; 617 /* cnt == -1 means infinite, but rings have a finite amount 618 * of buffers and the int is large enough that we never wrap, 619 * so we can omit checking for -1 620 */ 621 for (c=0; c < n && cnt != got; c++) { 622 /* compute current ring to use */ 623 struct netmap_ring *ring; 624 625 ri = d->cur_rx_ring + c; 626 if (ri > d->last_rx_ring) 627 ri = d->first_rx_ring; 628 ring = NETMAP_RXRING(d->nifp, ri); 629 for ( ; !nm_ring_empty(ring) && cnt != got; got++) { 630 u_int i = ring->cur; 631 u_int idx = ring->slot[i].buf_idx; 632 u_char *buf = (u_char *)NETMAP_BUF(ring, idx); 633 634 // __builtin_prefetch(buf); 635 d->hdr.len = d->hdr.caplen = ring->slot[i].len; 636 d->hdr.ts = ring->ts; 637 cb(arg, &d->hdr, buf); 638 ring->head = ring->cur = nm_ring_next(ring, i); 639 } 640 } 641 d->cur_rx_ring = ri; 642 return got; 643 } 644 645 static u_char * 646 nm_nextpkt(struct nm_desc *d, struct nm_pkthdr *hdr) 647 { 648 int ri = d->cur_rx_ring; 649 650 do { 651 /* compute current ring to use */ 652 struct netmap_ring *ring = NETMAP_RXRING(d->nifp, ri); 653 if (!nm_ring_empty(ring)) { 654 u_int i = ring->cur; 655 u_int idx = ring->slot[i].buf_idx; 656 u_char *buf = (u_char *)NETMAP_BUF(ring, idx); 657 658 // __builtin_prefetch(buf); 659 hdr->ts = ring->ts; 660 hdr->len = hdr->caplen = ring->slot[i].len; 661 ring->cur = nm_ring_next(ring, i); 662 /* we could postpone advancing head if we want 663 * to hold the buffer. This can be supported in 664 * the future. 665 */ 666 ring->head = ring->cur; 667 d->cur_rx_ring = ri; 668 return buf; 669 } 670 ri++; 671 if (ri > d->last_rx_ring) 672 ri = d->first_rx_ring; 673 } while (ri != d->cur_rx_ring); 674 return NULL; /* nothing found */ 675 } 676 677 #endif /* !HAVE_NETMAP_WITH_LIBS */ 678 679 #endif /* NETMAP_WITH_LIBS */ 680 681 #endif /* _NET_NETMAP_USER_H_ */ 682