1 /* uipc_socket2.c 4.22 82/03/19 */ 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 #include "../net/in.h" 16 #include "../net/in_systm.h" 17 18 /* 19 * Primitive routines for operating on sockets and socket buffers 20 */ 21 22 /* 23 * Procedures to manipulate state flags of socket 24 * and do appropriate wakeups. Normal sequence is that 25 * soisconnecting() is called during processing of connect() call, 26 * resulting in an eventual call to soisconnected() if/when the 27 * connection is established. When the connection is torn down 28 * soisdisconnecting() is called during processing of disconnect() call, 29 * and soisdisconnected() is called when the connection to the peer 30 * is totally severed. The semantics of these routines are such that 31 * connectionless protocols can call soisconnected() and soisdisconnected() 32 * only, bypassing the in-progress calls when setting up a ``connection'' 33 * takes no time. 34 * 35 * When higher level protocols are implemented in 36 * the kernel, the wakeups done here will sometimes 37 * be implemented as software-interrupt process scheduling. 38 */ 39 40 soisconnecting(so) 41 struct socket *so; 42 { 43 44 so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING); 45 so->so_state |= SS_ISCONNECTING; 46 wakeup((caddr_t)&so->so_timeo); 47 } 48 49 soisconnected(so) 50 struct socket *so; 51 { 52 53 so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING); 54 so->so_state |= SS_ISCONNECTED; 55 wakeup((caddr_t)&so->so_timeo); 56 sorwakeup(so); 57 sowwakeup(so); 58 } 59 60 soisdisconnecting(so) 61 struct socket *so; 62 { 63 64 so->so_state &= ~SS_ISCONNECTING; 65 so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE); 66 wakeup((caddr_t)&so->so_timeo); 67 sowwakeup(so); 68 sorwakeup(so); 69 } 70 71 soisdisconnected(so) 72 struct socket *so; 73 { 74 75 so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING); 76 so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE); 77 wakeup((caddr_t)&so->so_timeo); 78 sowwakeup(so); 79 sorwakeup(so); 80 } 81 82 /* 83 * Socantsendmore indicates that no more data will be sent on the 84 * socket; it would normally be applied to a socket when the user 85 * informs the system that no more data is to be sent, by the protocol 86 * code (in case PRU_SHUTDOWN). Socantrcvmore indicates that no more data 87 * will be received, and will normally be applied to the socket by a 88 * protocol when it detects that the peer will send no more data. 89 * Data queued for reading in the socket may yet be read. 90 */ 91 92 socantsendmore(so) 93 struct socket *so; 94 { 95 96 so->so_state |= SS_CANTSENDMORE; 97 sowwakeup(so); 98 } 99 100 socantrcvmore(so) 101 struct socket *so; 102 { 103 104 so->so_state |= SS_CANTRCVMORE; 105 sorwakeup(so); 106 } 107 108 /* 109 * Socket select/wakeup routines. 110 */ 111 112 /* 113 * Interface routine to select() system 114 * call for sockets. 115 */ 116 soselect(so, rw) 117 register struct socket *so; 118 int rw; 119 { 120 int s = splnet(); 121 122 switch (rw) { 123 124 case FREAD: 125 if (soreadable(so)) { 126 splx(s); 127 return (1); 128 } 129 sbselqueue(&so->so_rcv); 130 break; 131 132 case FWRITE: 133 if (sowriteable(so)) { 134 splx(s); 135 return (1); 136 } 137 sbselqueue(&so->so_snd); 138 break; 139 } 140 splx(s); 141 return (0); 142 } 143 144 /* 145 * Queue a process for a select on a socket buffer. 146 */ 147 sbselqueue(sb) 148 struct sockbuf *sb; 149 { 150 register struct proc *p; 151 152 if ((p = sb->sb_sel) && p->p_wchan == (caddr_t)&selwait) 153 sb->sb_flags |= SB_COLL; 154 else 155 sb->sb_sel = u.u_procp; 156 } 157 158 /* 159 * Wait for data to arrive at/drain from a socket buffer. 160 */ 161 sbwait(sb) 162 struct sockbuf *sb; 163 { 164 165 sb->sb_flags |= SB_WAIT; 166 sleep((caddr_t)&sb->sb_cc, PZERO+1); 167 } 168 169 /* 170 * Wakeup processes waiting on a socket buffer. 171 */ 172 sbwakeup(sb) 173 struct sockbuf *sb; 174 { 175 176 if (sb->sb_sel) { 177 selwakeup(sb->sb_sel, sb->sb_flags & SB_COLL); 178 sb->sb_sel = 0; 179 sb->sb_flags &= ~SB_COLL; 180 } 181 if (sb->sb_flags & SB_WAIT) { 182 sb->sb_flags &= ~SB_WAIT; 183 wakeup((caddr_t)&sb->sb_cc); 184 } 185 } 186 187 /* 188 * Socket buffer (struct sockbuf) utility routines. 189 * 190 * Each socket contains two socket buffers: one for sending data and 191 * one for receiving data. Each buffer contains a queue of mbufs, 192 * information about the number of mbufs and amount of data in the 193 * queue, and other fields allowing select() statements and notification 194 * on data availability to be implemented. 195 * 196 * Before using a new socket structure it is first necessary to reserve 197 * buffer space to the socket, by calling sbreserve. This commits 198 * some of the available buffer space in the system buffer pool for the 199 * socket. The space should be released by calling sbrelease when the 200 * socket is destroyed. 201 * 202 * The routine sbappend() is normally called to append new mbufs 203 * to a socket buffer, after checking that adequate space is available 204 * comparing the function spspace() with the amount of data to be added. 205 * Data is normally removed from a socket buffer in a protocol by 206 * first calling m_copy on the socket buffer mbuf chain and sending this 207 * to a peer, and then removing the data from the socket buffer with 208 * sbdrop when the data is acknowledged by the peer (or immediately 209 * in the case of unreliable protocols.) 210 * 211 * Protocols which do not require connections place both source address 212 * and data information in socket buffer queues. The source addresses 213 * are stored in single mbufs after each data item, and are easily found 214 * as the data items are all marked with end of record markers. The 215 * sbappendaddr() routine stores a datum and associated address in 216 * a socket buffer. Note that, unlike sbappend(), this routine checks 217 * for the caller that there will be enough space to store the data. 218 * It fails if there is not enough space, or if it cannot find 219 * a mbuf to store the address in. 220 * 221 * The higher-level routines sosend and soreceive (in socket.c) 222 * also add data to, and remove data from socket buffers repectively. 223 */ 224 225 /* 226 * Allot mbufs to a sockbuf. 227 */ 228 sbreserve(sb, cc) 229 struct sockbuf *sb; 230 { 231 232 if (m_reserve((cc*2)/MSIZE) == 0) 233 return (0); 234 sb->sb_hiwat = cc; 235 sb->sb_mbmax = cc*2; 236 return (1); 237 } 238 239 /* 240 * Free mbufs held by a socket, and reserved mbuf space. 241 */ 242 sbrelease(sb) 243 struct sockbuf *sb; 244 { 245 246 sbflush(sb); 247 m_release(sb->sb_mbmax/MSIZE); 248 sb->sb_hiwat = sb->sb_mbmax = 0; 249 } 250 251 /* 252 * Routines to add (at the end) and remove (from the beginning) 253 * data from a mbuf queue. 254 */ 255 256 /* 257 * Append mbuf queue m to sockbuf sb. 258 */ 259 sbappend(sb, m) 260 register struct mbuf *m; 261 register struct sockbuf *sb; 262 { 263 register struct mbuf *n; 264 265 n = sb->sb_mb; 266 if (n) 267 while (n->m_next) 268 n = n->m_next; 269 while (m) { 270 if (m->m_len == 0 && (int)m->m_act == 0) { 271 m = m_free(m); 272 continue; 273 } 274 if (n && n->m_off <= MMAXOFF && m->m_off <= MMAXOFF && 275 (int)n->m_act == 0 && (int)m->m_act == 0 && 276 (n->m_off + n->m_len + m->m_len) <= MMAXOFF) { 277 bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len, 278 (unsigned)m->m_len); 279 n->m_len += m->m_len; 280 sb->sb_cc += m->m_len; 281 m = m_free(m); 282 continue; 283 } 284 sballoc(sb, m); 285 if (n == 0) 286 sb->sb_mb = m; 287 else 288 n->m_next = m; 289 n = m; 290 m = m->m_next; 291 n->m_next = 0; 292 } 293 } 294 295 /* 296 * Append data and address. 297 * Return 0 if no space in sockbuf or if 298 * can't get mbuf to stuff address in. 299 */ 300 sbappendaddr(sb, asa, m0) 301 struct sockbuf *sb; 302 struct sockaddr *asa; 303 struct mbuf *m0; 304 { 305 struct sockaddr *msa; 306 register struct mbuf *m; 307 register int len = sizeof (struct sockaddr); 308 309 m = m0; 310 if (m == 0) 311 panic("sbappendaddr"); 312 for (;;) { 313 len += m->m_len; 314 if (m->m_next == 0) { 315 m->m_act = (struct mbuf *)1; 316 break; 317 } 318 m = m->m_next; 319 } 320 if (len > sbspace(sb)) 321 return (0); 322 m = m_get(M_DONTWAIT); 323 if (m == 0) 324 return (0); 325 m->m_off = MMINOFF; 326 m->m_len = sizeof (struct sockaddr); 327 msa = mtod(m, struct sockaddr *); 328 *msa = *asa; 329 m->m_act = (struct mbuf *)1; 330 sbappend(sb, m); 331 sbappend(sb, m0); 332 return (1); 333 } 334 335 /* 336 * Free all mbufs on a sockbuf mbuf chain. 337 * Check that resource allocations return to 0. 338 */ 339 sbflush(sb) 340 struct sockbuf *sb; 341 { 342 343 if (sb->sb_flags & SB_LOCK) 344 panic("sbflush"); 345 if (sb->sb_cc) 346 sbdrop(sb, sb->sb_cc); 347 if (sb->sb_cc || sb->sb_mbcnt || sb->sb_mb) 348 panic("sbflush 2"); 349 } 350 351 /* 352 * Drop data from (the front of) a sockbuf chain. 353 */ 354 sbdrop(sb, len) 355 register struct sockbuf *sb; 356 register int len; 357 { 358 register struct mbuf *m = sb->sb_mb, *mn; 359 360 while (len > 0) { 361 if (m == 0) 362 panic("sbdrop"); 363 if (m->m_len > len) { 364 m->m_len -= len; 365 m->m_off += len; 366 sb->sb_cc -= len; 367 break; 368 } 369 len -= m->m_len; 370 sbfree(sb, m); 371 MFREE(m, mn); 372 m = mn; 373 } 374 sb->sb_mb = m; 375 } 376