1 /* 2 * Copyright (c) 1995 Danny Gasparovski. 3 * 4 * Please read the file COPYRIGHT for the 5 * terms and conditions of the copyright. 6 */ 7 8 #include <slirp.h> 9 10 int if_queued = 0; /* Number of packets queued so far */ 11 12 struct mbuf if_fastq; /* fast queue (for interactive data) */ 13 struct mbuf if_batchq; /* queue for non-interactive data */ 14 struct mbuf *next_m; /* Pointer to next mbuf to output */ 15 16 #define ifs_init(ifm) ((ifm)->ifs_next = (ifm)->ifs_prev = (ifm)) 17 18 static void ifs_insque(struct mbuf * ifm,struct mbuf * ifmhead)19 ifs_insque(struct mbuf *ifm, struct mbuf *ifmhead) 20 { 21 ifm->ifs_next = ifmhead->ifs_next; 22 ifmhead->ifs_next = ifm; 23 ifm->ifs_prev = ifmhead; 24 ifm->ifs_next->ifs_prev = ifm; 25 } 26 27 static void ifs_remque(struct mbuf * ifm)28 ifs_remque(struct mbuf *ifm) 29 { 30 ifm->ifs_prev->ifs_next = ifm->ifs_next; 31 ifm->ifs_next->ifs_prev = ifm->ifs_prev; 32 } 33 34 void if_init(void)35 if_init(void) 36 { 37 if_fastq.ifq_next = if_fastq.ifq_prev = &if_fastq; 38 if_batchq.ifq_next = if_batchq.ifq_prev = &if_batchq; 39 // sl_compress_init(&comp_s); 40 next_m = &if_batchq; 41 } 42 43 #if 0 44 /* 45 * This shouldn't be needed since the modem is blocking and 46 * we don't expect any signals, but what the hell.. 47 */ 48 inline int 49 writen(fd, bptr, n) 50 int fd; 51 char *bptr; 52 int n; 53 { 54 int ret; 55 int total; 56 57 /* This should succeed most of the time */ 58 ret = send(fd, bptr, n,0); 59 if (ret == n || ret <= 0) 60 return ret; 61 62 /* Didn't write everything, go into the loop */ 63 total = ret; 64 while (n > total) { 65 ret = send(fd, bptr+total, n-total,0); 66 if (ret <= 0) 67 return ret; 68 total += ret; 69 } 70 return total; 71 } 72 73 /* 74 * if_input - read() the tty, do "top level" processing (ie: check for any escapes), 75 * and pass onto (*ttyp->if_input) 76 * 77 * XXXXX Any zeros arriving by themselves are NOT placed into the arriving packet. 78 */ 79 #define INBUFF_SIZE 2048 /* XXX */ 80 void 81 if_input(ttyp) 82 struct ttys *ttyp; 83 { 84 u_char if_inbuff[INBUFF_SIZE]; 85 int if_n; 86 87 DEBUG_CALL("if_input"); 88 DEBUG_ARG("ttyp = %lx", (long)ttyp); 89 90 if_n = recv(ttyp->fd, (char *)if_inbuff, INBUFF_SIZE,0); 91 92 DEBUG_MISC((dfd, " read %d bytes\n", if_n)); 93 94 if (if_n <= 0) { 95 if (if_n == 0 || (errno != EINTR && errno != EAGAIN)) { 96 if (ttyp->up) 97 link_up--; 98 tty_detached(ttyp, 0); 99 } 100 return; 101 } 102 if (if_n == 1) { 103 if (*if_inbuff == '0') { 104 ttyp->ones = 0; 105 if (++ttyp->zeros >= 5) 106 slirp_exit(0); 107 return; 108 } 109 if (*if_inbuff == '1') { 110 ttyp->zeros = 0; 111 if (++ttyp->ones >= 5) 112 tty_detached(ttyp, 0); 113 return; 114 } 115 } 116 ttyp->ones = ttyp->zeros = 0; 117 118 (*ttyp->if_input)(ttyp, if_inbuff, if_n); 119 } 120 #endif 121 122 /* 123 * if_output: Queue packet into an output queue. 124 * There are 2 output queue's, if_fastq and if_batchq. 125 * Each output queue is a doubly linked list of double linked lists 126 * of mbufs, each list belonging to one "session" (socket). This 127 * way, we can output packets fairly by sending one packet from each 128 * session, instead of all the packets from one session, then all packets 129 * from the next session, etc. Packets on the if_fastq get absolute 130 * priority, but if one session hogs the link, it gets "downgraded" 131 * to the batchq until it runs out of packets, then it'll return 132 * to the fastq (eg. if the user does an ls -alR in a telnet session, 133 * it'll temporarily get downgraded to the batchq) 134 */ 135 void if_output(struct socket * so,struct mbuf * ifm)136 if_output(struct socket *so, struct mbuf *ifm) 137 { 138 struct mbuf *ifq; 139 int on_fastq = 1; 140 141 DEBUG_CALL("if_output"); 142 DEBUG_ARG("so = %lx", (long)so); 143 DEBUG_ARG("ifm = %lx", (long)ifm); 144 145 /* 146 * First remove the mbuf from m_usedlist, 147 * since we're gonna use m_next and m_prev ourselves 148 * XXX Shouldn't need this, gotta change dtom() etc. 149 */ 150 if (ifm->m_flags & M_USEDLIST) { 151 remque(ifm); 152 ifm->m_flags &= ~M_USEDLIST; 153 } 154 155 /* 156 * See if there's already a batchq list for this session. 157 * This can include an interactive session, which should go on fastq, 158 * but gets too greedy... hence it'll be downgraded from fastq to batchq. 159 * We mustn't put this packet back on the fastq (or we'll send it out of order) 160 * XXX add cache here? 161 */ 162 for (ifq = if_batchq.ifq_prev; ifq != &if_batchq; ifq = ifq->ifq_prev) { 163 if (so == ifq->ifq_so) { 164 /* A match! */ 165 ifm->ifq_so = so; 166 ifs_insque(ifm, ifq->ifs_prev); 167 goto diddit; 168 } 169 } 170 171 /* No match, check which queue to put it on */ 172 if (so && (so->so_iptos & IPTOS_LOWDELAY)) { 173 ifq = if_fastq.ifq_prev; 174 on_fastq = 1; 175 /* 176 * Check if this packet is a part of the last 177 * packet's session 178 */ 179 if (ifq->ifq_so == so) { 180 ifm->ifq_so = so; 181 ifs_insque(ifm, ifq->ifs_prev); 182 goto diddit; 183 } 184 } else 185 ifq = if_batchq.ifq_prev; 186 187 /* Create a new doubly linked list for this session */ 188 ifm->ifq_so = so; 189 ifs_init(ifm); 190 insque(ifm, ifq); 191 192 diddit: 193 ++if_queued; 194 195 if (so) { 196 /* Update *_queued */ 197 so->so_queued++; 198 so->so_nqueued++; 199 /* 200 * Check if the interactive session should be downgraded to 201 * the batchq. A session is downgraded if it has queued 6 202 * packets without pausing, and at least 3 of those packets 203 * have been sent over the link 204 * (XXX These are arbitrary numbers, probably not optimal..) 205 */ 206 if (on_fastq && ((so->so_nqueued >= 6) && 207 (so->so_nqueued - so->so_queued) >= 3)) { 208 209 /* Remove from current queue... */ 210 remque(ifm->ifs_next); 211 212 /* ...And insert in the new. That'll teach ya! */ 213 insque(ifm->ifs_next, &if_batchq); 214 } 215 } 216 217 #ifndef FULL_BOLT 218 /* 219 * This prevents us from malloc()ing too many mbufs 220 */ 221 if (link_up) { 222 /* if_start will check towrite */ 223 if_start(); 224 } 225 #endif 226 } 227 228 /* 229 * Send a packet 230 * We choose a packet based on it's position in the output queues; 231 * If there are packets on the fastq, they are sent FIFO, before 232 * everything else. Otherwise we choose the first packet from the 233 * batchq and send it. the next packet chosen will be from the session 234 * after this one, then the session after that one, and so on.. So, 235 * for example, if there are 3 ftp session's fighting for bandwidth, 236 * one packet will be sent from the first session, then one packet 237 * from the second session, then one packet from the third, then back 238 * to the first, etc. etc. 239 */ 240 void if_start(void)241 if_start(void) 242 { 243 struct mbuf *ifm, *ifqt; 244 245 DEBUG_CALL("if_start"); 246 247 if (if_queued == 0) 248 return; /* Nothing to do */ 249 250 again: 251 /* check if we can really output */ 252 if (!slirp_can_output()) 253 return; 254 255 /* 256 * See which queue to get next packet from 257 * If there's something in the fastq, select it immediately 258 */ 259 if (if_fastq.ifq_next != &if_fastq) { 260 ifm = if_fastq.ifq_next; 261 } else { 262 /* Nothing on fastq, see if next_m is valid */ 263 if (next_m != &if_batchq) 264 ifm = next_m; 265 else 266 ifm = if_batchq.ifq_next; 267 268 /* Set which packet to send on next iteration */ 269 next_m = ifm->ifq_next; 270 } 271 /* Remove it from the queue */ 272 ifqt = ifm->ifq_prev; 273 remque(ifm); 274 --if_queued; 275 276 /* If there are more packets for this session, re-queue them */ 277 if (ifm->ifs_next != /* ifm->ifs_prev != */ ifm) { 278 insque(ifm->ifs_next, ifqt); 279 ifs_remque(ifm); 280 } 281 282 /* Update so_queued */ 283 if (ifm->ifq_so) { 284 if (--ifm->ifq_so->so_queued == 0) 285 /* If there's no more queued, reset nqueued */ 286 ifm->ifq_so->so_nqueued = 0; 287 } 288 289 /* Encapsulate the packet for sending */ 290 if_encap((uint8_t *)ifm->m_data, ifm->m_len); 291 292 m_free(ifm); 293 294 if (if_queued) 295 goto again; 296 } 297