1 /* uipc_socket2.c 4.32 82/12/14 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/dir.h" 6 #include "../h/user.h" 7 #include "../h/proc.h" 8 #include "../h/file.h" 9 #include "../h/inode.h" 10 #include "../h/buf.h" 11 #include "../h/mbuf.h" 12 #include "../h/protosw.h" 13 #include "../h/socket.h" 14 #include "../h/socketvar.h" 15 16 /* 17 * Primitive routines for operating on sockets and socket buffers 18 */ 19 20 /* 21 * Procedures to manipulate state flags of socket 22 * and do appropriate wakeups. Normal sequence from the 23 * active (originating) side is that soisconnecting() is 24 * called during processing of connect() call, 25 * resulting in an eventual call to soisconnected() if/when the 26 * connection is established. When the connection is torn down 27 * soisdisconnecting() is called during processing of disconnect() call, 28 * and soisdisconnected() is called when the connection to the peer 29 * is totally severed. The semantics of these routines are such that 30 * connectionless protocols can call soisconnected() and soisdisconnected() 31 * only, bypassing the in-progress calls when setting up a ``connection'' 32 * takes no time. 33 * 34 * From the passive side, a socket is created with SO_ACCEPTCONN 35 * creating two queues of sockets: so_q0 for connections in progress 36 * and so_q for connections already made and awaiting user acceptance. 37 * As a protocol is preparing incoming connections, it creates a socket 38 * structure queued on so_q0 by calling sonewconn(). When the connection 39 * is established, soisconnected() is called, and transfers the 40 * socket structure to so_q, making it available to accept(). 41 * 42 * If a SO_ACCEPTCONN socket is closed with sockets on either 43 * so_q0 or so_q, these sockets are dropped. 44 * 45 * If and when higher level protocols are implemented in 46 * the kernel, the wakeups done here will sometimes 47 * be implemented as software-interrupt process scheduling. 48 */ 49 50 soisconnecting(so) 51 struct socket *so; 52 { 53 54 so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING); 55 so->so_state |= SS_ISCONNECTING; 56 wakeup((caddr_t)&so->so_timeo); 57 } 58 59 soisconnected(so) 60 struct socket *so; 61 { 62 register struct socket *head = so->so_head; 63 64 if (head) { 65 if (soqremque(so, 0) == 0) 66 panic("soisconnected"); 67 soqinsque(head, so, 1); 68 wakeup((caddr_t)&head->so_timeo); 69 } 70 so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING); 71 so->so_state |= SS_ISCONNECTED; 72 wakeup((caddr_t)&so->so_timeo); 73 sorwakeup(so); 74 sowwakeup(so); 75 } 76 77 soisdisconnecting(so) 78 struct socket *so; 79 { 80 81 so->so_state &= ~SS_ISCONNECTING; 82 so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE); 83 wakeup((caddr_t)&so->so_timeo); 84 sowwakeup(so); 85 sorwakeup(so); 86 } 87 88 soisdisconnected(so) 89 struct socket *so; 90 { 91 92 so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING); 93 so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE); 94 wakeup((caddr_t)&so->so_timeo); 95 sowwakeup(so); 96 sorwakeup(so); 97 } 98 99 /* 100 * When an attempt at a new connection is noted on a socket 101 * which accepts connections, sonewconn is called. If the 102 * connection is possible (subject to space constraints, etc.) 103 * then we allocate a new structure, propoerly linked into the 104 * data structure of the original socket, and return this. 105 */ 106 struct socket * 107 sonewconn(head) 108 register struct socket *head; 109 { 110 register struct socket *so; 111 struct mbuf *m; 112 113 if (head->so_qlen + head->so_q0len > 3 * head->so_qlimit / 2) 114 goto bad; 115 m = m_getclr(M_DONTWAIT, MT_SOCKET); 116 if (m == 0) 117 goto bad; 118 so = mtod(m, struct socket *); 119 so->so_type = head->so_type; 120 so->so_options = head->so_options &~ SO_ACCEPTCONN; 121 so->so_linger = head->so_linger; 122 so->so_state = head->so_state; 123 so->so_proto = head->so_proto; 124 so->so_timeo = head->so_timeo; 125 so->so_pgrp = head->so_pgrp; 126 soqinsque(head, so, 0); 127 if ((*so->so_proto->pr_usrreq)(so, PRU_ATTACH, 0, 0, 0)) { 128 (void) soqremque(so, 0); 129 (void) m_free(m); 130 goto bad; 131 } 132 return (so); 133 bad: 134 return ((struct socket *)0); 135 } 136 137 soqinsque(head, so, q) 138 register struct socket *head, *so; 139 int q; 140 { 141 142 so->so_head = head; 143 if (q == 0) { 144 head->so_q0len++; 145 so->so_q0 = head->so_q0; 146 head->so_q0 = so; 147 } else { 148 head->so_qlen++; 149 so->so_q = head->so_q; 150 head->so_q = so; 151 } 152 } 153 154 soqremque(so, q) 155 register struct socket *so; 156 int q; 157 { 158 register struct socket *head, *prev, *next; 159 160 head = so->so_head; 161 prev = head; 162 for (;;) { 163 next = q ? prev->so_q : prev->so_q0; 164 if (next == so) 165 break; 166 if (next == head) 167 return (0); 168 prev = next; 169 } 170 if (q == 0) { 171 prev->so_q0 = next->so_q0; 172 head->so_q0len--; 173 } else { 174 prev->so_q = next->so_q; 175 head->so_qlen--; 176 } 177 next->so_q0 = next->so_q = 0; 178 next->so_head = 0; 179 return (1); 180 } 181 182 /* 183 * Socantsendmore indicates that no more data will be sent on the 184 * socket; it would normally be applied to a socket when the user 185 * informs the system that no more data is to be sent, by the protocol 186 * code (in case PRU_SHUTDOWN). Socantrcvmore indicates that no more data 187 * will be received, and will normally be applied to the socket by a 188 * protocol when it detects that the peer will send no more data. 189 * Data queued for reading in the socket may yet be read. 190 */ 191 192 socantsendmore(so) 193 struct socket *so; 194 { 195 196 so->so_state |= SS_CANTSENDMORE; 197 sowwakeup(so); 198 } 199 200 socantrcvmore(so) 201 struct socket *so; 202 { 203 204 so->so_state |= SS_CANTRCVMORE; 205 sorwakeup(so); 206 } 207 208 /* 209 * Socket select/wakeup routines. 210 */ 211 212 /* 213 * Interface routine to select() system 214 * call for sockets. 215 */ 216 soselect(so, rw) 217 register struct socket *so; 218 int rw; 219 { 220 int s = splnet(); 221 222 switch (rw) { 223 224 case FREAD: 225 if (soreadable(so)) { 226 splx(s); 227 return (1); 228 } 229 sbselqueue(&so->so_rcv); 230 break; 231 232 case FWRITE: 233 if (sowriteable(so)) { 234 splx(s); 235 return (1); 236 } 237 sbselqueue(&so->so_snd); 238 break; 239 } 240 splx(s); 241 return (0); 242 } 243 244 /* 245 * Queue a process for a select on a socket buffer. 246 */ 247 sbselqueue(sb) 248 struct sockbuf *sb; 249 { 250 register struct proc *p; 251 252 if ((p = sb->sb_sel) && p->p_wchan == (caddr_t)&selwait) 253 sb->sb_flags |= SB_COLL; 254 else 255 sb->sb_sel = u.u_procp; 256 } 257 258 /* 259 * Wait for data to arrive at/drain from a socket buffer. 260 */ 261 sbwait(sb) 262 struct sockbuf *sb; 263 { 264 265 sb->sb_flags |= SB_WAIT; 266 sleep((caddr_t)&sb->sb_cc, PZERO+1); 267 } 268 269 /* 270 * Wakeup processes waiting on a socket buffer. 271 */ 272 sbwakeup(sb) 273 struct sockbuf *sb; 274 { 275 276 if (sb->sb_sel) { 277 selwakeup(sb->sb_sel, sb->sb_flags & SB_COLL); 278 sb->sb_sel = 0; 279 sb->sb_flags &= ~SB_COLL; 280 } 281 if (sb->sb_flags & SB_WAIT) { 282 sb->sb_flags &= ~SB_WAIT; 283 wakeup((caddr_t)&sb->sb_cc); 284 } 285 } 286 287 /* 288 * Socket buffer (struct sockbuf) utility routines. 289 * 290 * Each socket contains two socket buffers: one for sending data and 291 * one for receiving data. Each buffer contains a queue of mbufs, 292 * information about the number of mbufs and amount of data in the 293 * queue, and other fields allowing select() statements and notification 294 * on data availability to be implemented. 295 * 296 * Before using a new socket structure it is first necessary to reserve 297 * buffer space to the socket, by calling sbreserve. This commits 298 * some of the available buffer space in the system buffer pool for the 299 * socket. The space should be released by calling sbrelease when the 300 * socket is destroyed. 301 * 302 * The routine sbappend() is normally called to append new mbufs 303 * to a socket buffer, after checking that adequate space is available 304 * comparing the function spspace() with the amount of data to be added. 305 * Data is normally removed from a socket buffer in a protocol by 306 * first calling m_copy on the socket buffer mbuf chain and sending this 307 * to a peer, and then removing the data from the socket buffer with 308 * sbdrop when the data is acknowledged by the peer (or immediately 309 * in the case of unreliable protocols.) 310 * 311 * Protocols which do not require connections place both source address 312 * and data information in socket buffer queues. The source addresses 313 * are stored in single mbufs after each data item, and are easily found 314 * as the data items are all marked with end of record markers. The 315 * sbappendaddr() routine stores a datum and associated address in 316 * a socket buffer. Note that, unlike sbappend(), this routine checks 317 * for the caller that there will be enough space to store the data. 318 * It fails if there is not enough space, or if it cannot find 319 * a mbuf to store the address in. 320 * 321 * The higher-level routines sosend and soreceive (in socket.c) 322 * also add data to, and remove data from socket buffers repectively. 323 */ 324 325 soreserve(so, sndcc, rcvcc) 326 struct socket *so; 327 int sndcc, rcvcc; 328 { 329 330 if (sbreserve(&so->so_snd, sndcc) == 0) 331 goto bad; 332 if (sbreserve(&so->so_rcv, rcvcc) == 0) 333 goto bad2; 334 return (0); 335 bad2: 336 sbrelease(&so->so_snd); 337 bad: 338 return (ENOBUFS); 339 } 340 341 /* 342 * Allot mbufs to a sockbuf. 343 */ 344 sbreserve(sb, cc) 345 struct sockbuf *sb; 346 { 347 348 /* someday maybe this routine will fail... */ 349 sb->sb_hiwat = cc; 350 sb->sb_mbmax = cc*2; 351 return (1); 352 } 353 354 /* 355 * Free mbufs held by a socket, and reserved mbuf space. 356 */ 357 sbrelease(sb) 358 struct sockbuf *sb; 359 { 360 361 sbflush(sb); 362 sb->sb_hiwat = sb->sb_mbmax = 0; 363 } 364 365 /* 366 * Routines to add (at the end) and remove (from the beginning) 367 * data from a mbuf queue. 368 */ 369 370 /* 371 * Append mbuf queue m to sockbuf sb. 372 */ 373 sbappend(sb, m) 374 register struct mbuf *m; 375 register struct sockbuf *sb; 376 { 377 register struct mbuf *n; 378 379 SBCHECK(sb, "sbappend begin"); 380 #ifdef notdef 381 { struct mbuf *p; 382 printf("sba: "); 383 for (p = sb->sb_mb; p; p = p->m_next) printf("%x:(%x,%d) ",p,p->m_off,p->m_len); 384 printf("+= "); 385 for (p = m; p; p = p->m_next) printf("%x:(%x,%d) ",p,p->m_off,p->m_len); 386 printf("\n"); 387 } 388 #endif 389 n = sb->sb_mb; 390 if (n) 391 while (n->m_next) 392 n = n->m_next; 393 while (m) { 394 if (m->m_len == 0 && (int)m->m_act == 0) { 395 m = m_free(m); 396 continue; 397 } 398 if (n && n->m_off <= MMAXOFF && m->m_off <= MMAXOFF && 399 (int)n->m_act == 0 && (int)m->m_act == 0 && 400 (n->m_off + n->m_len + m->m_len) <= MMAXOFF) { 401 bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len, 402 (unsigned)m->m_len); 403 n->m_len += m->m_len; 404 sb->sb_cc += m->m_len; 405 m = m_free(m); 406 continue; 407 } 408 sballoc(sb, m); 409 if (n == 0) 410 sb->sb_mb = m; 411 else 412 n->m_next = m; 413 n = m; 414 m = m->m_next; 415 n->m_next = 0; 416 } 417 #ifdef notdef 418 { struct mbuf *p; 419 printf("res: "); 420 for (p = sb->sb_mb; p; p = p->m_next) printf("%x:(%x,%d) ",p,p->m_off,p->m_len); 421 printf("+= "); 422 for (p = m; p; p = p->m_next) printf("%x:(%x,%d) ",p,p->m_off,p->m_len); 423 printf("\n"); 424 } 425 #endif 426 SBCHECK(sb, "sbappend end"); 427 } 428 429 /* 430 * Append data and address. 431 * Return 0 if no space in sockbuf or if 432 * can't get mbuf to stuff address in. 433 */ 434 sbappendaddr(sb, asa, m0) 435 struct sockbuf *sb; 436 struct sockaddr *asa; 437 struct mbuf *m0; 438 { 439 struct sockaddr *msa; 440 register struct mbuf *m; 441 register int len = sizeof (struct sockaddr); 442 443 SBCHECK(sb, "sbappendaddr begin"); 444 m = m0; 445 if (m == 0) 446 panic("sbappendaddr"); 447 for (;;) { 448 len += m->m_len; 449 if (m->m_next == 0) { 450 m->m_act = (struct mbuf *)1; 451 break; 452 } 453 m = m->m_next; 454 } 455 if (len > sbspace(sb)) 456 return (0); 457 m = m_get(M_DONTWAIT, MT_SONAME); 458 if (m == 0) 459 return (0); 460 m->m_len = sizeof (struct sockaddr); 461 msa = mtod(m, struct sockaddr *); 462 *msa = *asa; 463 m->m_act = (struct mbuf *)1; 464 sbappend(sb, m); 465 sbappend(sb, m0); 466 SBCHECK(sb, "sbappendaddr end"); 467 return (1); 468 } 469 470 SBCHECK(sb, str) 471 struct sockbuf *sb; 472 char *str; 473 { 474 register int cnt = sb->sb_cc; 475 register int mbcnt = sb->sb_mbcnt; 476 register struct mbuf *m; 477 478 for (m = sb->sb_mb; m; m = m->m_next) { 479 cnt -= m->m_len; 480 mbcnt -= MSIZE; 481 if (m->m_off > MMAXOFF) 482 mbcnt -= CLBYTES; 483 } 484 if (cnt || mbcnt) { 485 printf("cnt %d mbcnt %d\n", cnt, mbcnt); 486 panic(str); 487 } 488 } 489 490 /* 491 * Free all mbufs on a sockbuf mbuf chain. 492 * Check that resource allocations return to 0. 493 */ 494 sbflush(sb) 495 struct sockbuf *sb; 496 { 497 498 if (sb->sb_flags & SB_LOCK) 499 panic("sbflush"); 500 if (sb->sb_cc) 501 sbdrop(sb, sb->sb_cc); 502 if (sb->sb_cc || sb->sb_mbcnt || sb->sb_mb) 503 panic("sbflush 2"); 504 } 505 506 /* 507 * Drop data from (the front of) a sockbuf chain. 508 */ 509 sbdrop(sb, len) 510 register struct sockbuf *sb; 511 register int len; 512 { 513 register struct mbuf *m = sb->sb_mb, *mn; 514 515 while (len > 0) { 516 if (m == 0) 517 panic("sbdrop"); 518 if (m->m_len > len) { 519 m->m_len -= len; 520 m->m_off += len; 521 sb->sb_cc -= len; 522 break; 523 } 524 len -= m->m_len; 525 sbfree(sb, m); 526 MFREE(m, mn); 527 m = mn; 528 } 529 sb->sb_mb = m; 530 } 531