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1.1 root 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_mtu, if_mru;
11: int if_comp;
12: int if_maxlinkhdr;
13: int if_queued = 0; /* Number of packets queued so far */
14: int if_thresh = 10; /* Number of packets queued before we start sending
15: * (to prevent allocing too many mbufs) */
16:
17: struct mbuf if_fastq; /* fast queue (for interactive data) */
18: struct mbuf if_batchq; /* queue for non-interactive data */
19: struct mbuf *next_m; /* Pointer to next mbuf to output */
20:
21: #define ifs_init(ifm) ((ifm)->ifs_next = (ifm)->ifs_prev = (ifm))
22:
23: void
24: ifs_insque(ifm, ifmhead)
25: struct mbuf *ifm, *ifmhead;
26: {
27: ifm->ifs_next = ifmhead->ifs_next;
28: ifmhead->ifs_next = ifm;
29: ifm->ifs_prev = ifmhead;
30: ifm->ifs_next->ifs_prev = ifm;
31: }
32:
33: void
34: ifs_remque(ifm)
35: struct mbuf *ifm;
36: {
37: ifm->ifs_prev->ifs_next = ifm->ifs_next;
38: ifm->ifs_next->ifs_prev = ifm->ifs_prev;
39: }
40:
41: void
42: if_init()
43: {
44: #if 0
45: /*
46: * Set if_maxlinkhdr to 48 because it's 40 bytes for TCP/IP,
47: * and 8 bytes for PPP, but need to have it on an 8byte boundary
48: */
49: #ifdef USE_PPP
50: if_maxlinkhdr = 48;
51: #else
52: if_maxlinkhdr = 40;
53: #endif
54: #else
55: /* 14 for ethernet + 40 */
56: if_maxlinkhdr = 14 + 40;
57: #endif
58: if_mtu = 1500;
59: if_mru = 1500;
60: if_comp = IF_AUTOCOMP;
61: if_fastq.ifq_next = if_fastq.ifq_prev = &if_fastq;
62: if_batchq.ifq_next = if_batchq.ifq_prev = &if_batchq;
63: // sl_compress_init(&comp_s);
64: next_m = &if_batchq;
65: }
66:
67: #if 0
68: /*
69: * This shouldn't be needed since the modem is blocking and
70: * we don't expect any signals, but what the hell..
71: */
72: inline int
73: writen(fd, bptr, n)
74: int fd;
75: char *bptr;
76: int n;
77: {
78: int ret;
79: int total;
80:
81: /* This should succeed most of the time */
82: ret = send(fd, bptr, n,0);
83: if (ret == n || ret <= 0)
84: return ret;
85:
86: /* Didn't write everything, go into the loop */
87: total = ret;
88: while (n > total) {
89: ret = send(fd, bptr+total, n-total,0);
90: if (ret <= 0)
91: return ret;
92: total += ret;
93: }
94: return total;
95: }
96:
97: /*
98: * if_input - read() the tty, do "top level" processing (ie: check for any escapes),
99: * and pass onto (*ttyp->if_input)
100: *
101: * XXXXX Any zeros arriving by themselves are NOT placed into the arriving packet.
102: */
103: #define INBUFF_SIZE 2048 /* XXX */
104: void
105: if_input(ttyp)
106: struct ttys *ttyp;
107: {
108: u_char if_inbuff[INBUFF_SIZE];
109: int if_n;
110:
111: DEBUG_CALL("if_input");
112: DEBUG_ARG("ttyp = %lx", (long)ttyp);
113:
114: if_n = recv(ttyp->fd, (char *)if_inbuff, INBUFF_SIZE,0);
115:
116: DEBUG_MISC((dfd, " read %d bytes\n", if_n));
117:
118: if (if_n <= 0) {
119: if (if_n == 0 || (errno != EINTR && errno != EAGAIN)) {
120: if (ttyp->up)
121: link_up--;
122: tty_detached(ttyp, 0);
123: }
124: return;
125: }
126: if (if_n == 1) {
127: if (*if_inbuff == '0') {
128: ttyp->ones = 0;
129: if (++ttyp->zeros >= 5)
130: slirp_exit(0);
131: return;
132: }
133: if (*if_inbuff == '1') {
134: ttyp->zeros = 0;
135: if (++ttyp->ones >= 5)
136: tty_detached(ttyp, 0);
137: return;
138: }
139: }
140: ttyp->ones = ttyp->zeros = 0;
141:
142: (*ttyp->if_input)(ttyp, if_inbuff, if_n);
143: }
144: #endif
145:
146: /*
147: * if_output: Queue packet into an output queue.
148: * There are 2 output queue's, if_fastq and if_batchq.
149: * Each output queue is a doubly linked list of double linked lists
150: * of mbufs, each list belonging to one "session" (socket). This
151: * way, we can output packets fairly by sending one packet from each
152: * session, instead of all the packets from one session, then all packets
153: * from the next session, etc. Packets on the if_fastq get absolute
154: * priority, but if one session hogs the link, it gets "downgraded"
155: * to the batchq until it runs out of packets, then it'll return
156: * to the fastq (eg. if the user does an ls -alR in a telnet session,
157: * it'll temporarily get downgraded to the batchq)
158: */
159: void
160: if_output(so, ifm)
161: struct socket *so;
162: struct mbuf *ifm;
163: {
164: struct mbuf *ifq;
165: int on_fastq = 1;
166:
167: DEBUG_CALL("if_output");
168: DEBUG_ARG("so = %lx", (long)so);
169: DEBUG_ARG("ifm = %lx", (long)ifm);
170:
171: /*
172: * First remove the mbuf from m_usedlist,
173: * since we're gonna use m_next and m_prev ourselves
174: * XXX Shouldn't need this, gotta change dtom() etc.
175: */
176: if (ifm->m_flags & M_USEDLIST) {
177: remque(ifm);
178: ifm->m_flags &= ~M_USEDLIST;
179: }
180:
181: /*
182: * See if there's already a batchq list for this session.
183: * This can include an interactive session, which should go on fastq,
184: * but gets too greedy... hence it'll be downgraded from fastq to batchq.
185: * We mustn't put this packet back on the fastq (or we'll send it out of order)
186: * XXX add cache here?
187: */
188: for (ifq = if_batchq.ifq_prev; ifq != &if_batchq; ifq = ifq->ifq_prev) {
189: if (so == ifq->ifq_so) {
190: /* A match! */
191: ifm->ifq_so = so;
192: ifs_insque(ifm, ifq->ifs_prev);
193: goto diddit;
194: }
195: }
196:
197: /* No match, check which queue to put it on */
198: if (so && (so->so_iptos & IPTOS_LOWDELAY)) {
199: ifq = if_fastq.ifq_prev;
200: on_fastq = 1;
201: /*
202: * Check if this packet is a part of the last
203: * packet's session
204: */
205: if (ifq->ifq_so == so) {
206: ifm->ifq_so = so;
207: ifs_insque(ifm, ifq->ifs_prev);
208: goto diddit;
209: }
210: } else
211: ifq = if_batchq.ifq_prev;
212:
213: /* Create a new doubly linked list for this session */
214: ifm->ifq_so = so;
215: ifs_init(ifm);
216: insque(ifm, ifq);
217:
218: diddit:
219: ++if_queued;
220:
221: if (so) {
222: /* Update *_queued */
223: so->so_queued++;
224: so->so_nqueued++;
225: /*
226: * Check if the interactive session should be downgraded to
227: * the batchq. A session is downgraded if it has queued 6
228: * packets without pausing, and at least 3 of those packets
229: * have been sent over the link
230: * (XXX These are arbitrary numbers, probably not optimal..)
231: */
232: if (on_fastq && ((so->so_nqueued >= 6) &&
233: (so->so_nqueued - so->so_queued) >= 3)) {
234:
235: /* Remove from current queue... */
236: remque(ifm->ifs_next);
237:
238: /* ...And insert in the new. That'll teach ya! */
239: insque(ifm->ifs_next, &if_batchq);
240: }
241: }
242:
243: #ifndef FULL_BOLT
244: /*
245: * This prevents us from malloc()ing too many mbufs
246: */
247: if (link_up) {
248: /* if_start will check towrite */
249: if_start();
250: }
251: #endif
252: }
253:
254: /*
255: * Send a packet
256: * We choose a packet based on it's position in the output queues;
257: * If there are packets on the fastq, they are sent FIFO, before
258: * everything else. Otherwise we choose the first packet from the
259: * batchq and send it. the next packet chosen will be from the session
260: * after this one, then the session after that one, and so on.. So,
261: * for example, if there are 3 ftp session's fighting for bandwidth,
262: * one packet will be sent from the first session, then one packet
263: * from the second session, then one packet from the third, then back
264: * to the first, etc. etc.
265: */
266: void
267: if_start(void)
268: {
269: struct mbuf *ifm, *ifqt;
270:
271: DEBUG_CALL("if_start");
272:
273: if (if_queued == 0)
274: return; /* Nothing to do */
275:
276: again:
277: /* check if we can really output */
278: if (!slirp_can_output())
279: return;
280:
281: /*
282: * See which queue to get next packet from
283: * If there's something in the fastq, select it immediately
284: */
285: if (if_fastq.ifq_next != &if_fastq) {
286: ifm = if_fastq.ifq_next;
287: } else {
288: /* Nothing on fastq, see if next_m is valid */
289: if (next_m != &if_batchq)
290: ifm = next_m;
291: else
292: ifm = if_batchq.ifq_next;
293:
294: /* Set which packet to send on next iteration */
295: next_m = ifm->ifq_next;
296: }
297: /* Remove it from the queue */
298: ifqt = ifm->ifq_prev;
299: remque(ifm);
300: --if_queued;
301:
302: /* If there are more packets for this session, re-queue them */
303: if (ifm->ifs_next != /* ifm->ifs_prev != */ ifm) {
304: insque(ifm->ifs_next, ifqt);
305: ifs_remque(ifm);
306: }
307:
308: /* Update so_queued */
309: if (ifm->ifq_so) {
310: if (--ifm->ifq_so->so_queued == 0)
311: /* If there's no more queued, reset nqueued */
312: ifm->ifq_so->so_nqueued = 0;
313: }
314:
315: /* Encapsulate the packet for sending */
316: if_encap(ifm->m_data, ifm->m_len);
317:
318: m_free(ifm);
319:
320: if (if_queued)
321: goto again;
322: }
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