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bellardf0cbd3e2004-04-22 00:10:48 +00001/*
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
bellardf0cbd3e2004-04-22 00:10:48 +000010#define ifs_init(ifm) ((ifm)->ifs_next = (ifm)->ifs_prev = (ifm))
11
blueswir1674bb262008-09-30 18:18:27 +000012static void
blueswir1a5f1b962008-08-17 20:21:51 +000013ifs_insque(struct mbuf *ifm, struct mbuf *ifmhead)
bellardf0cbd3e2004-04-22 00:10:48 +000014{
15 ifm->ifs_next = ifmhead->ifs_next;
16 ifmhead->ifs_next = ifm;
17 ifm->ifs_prev = ifmhead;
18 ifm->ifs_next->ifs_prev = ifm;
19}
20
blueswir1674bb262008-09-30 18:18:27 +000021static void
blueswir1a5f1b962008-08-17 20:21:51 +000022ifs_remque(struct mbuf *ifm)
bellardf0cbd3e2004-04-22 00:10:48 +000023{
24 ifm->ifs_prev->ifs_next = ifm->ifs_next;
25 ifm->ifs_next->ifs_prev = ifm->ifs_prev;
26}
27
28void
Jan Kiszka460fec62009-06-24 14:42:31 +020029if_init(Slirp *slirp)
bellardf0cbd3e2004-04-22 00:10:48 +000030{
Jan Kiszka460fec62009-06-24 14:42:31 +020031 slirp->if_fastq.ifq_next = slirp->if_fastq.ifq_prev = &slirp->if_fastq;
32 slirp->if_batchq.ifq_next = slirp->if_batchq.ifq_prev = &slirp->if_batchq;
33 slirp->next_m = &slirp->if_batchq;
bellardf0cbd3e2004-04-22 00:10:48 +000034}
35
bellardf0cbd3e2004-04-22 00:10:48 +000036/*
37 * if_output: Queue packet into an output queue.
ths5fafdf22007-09-16 21:08:06 +000038 * There are 2 output queue's, if_fastq and if_batchq.
bellardf0cbd3e2004-04-22 00:10:48 +000039 * Each output queue is a doubly linked list of double linked lists
40 * of mbufs, each list belonging to one "session" (socket). This
41 * way, we can output packets fairly by sending one packet from each
42 * session, instead of all the packets from one session, then all packets
ths5fafdf22007-09-16 21:08:06 +000043 * from the next session, etc. Packets on the if_fastq get absolute
bellardf0cbd3e2004-04-22 00:10:48 +000044 * priority, but if one session hogs the link, it gets "downgraded"
45 * to the batchq until it runs out of packets, then it'll return
46 * to the fastq (eg. if the user does an ls -alR in a telnet session,
47 * it'll temporarily get downgraded to the batchq)
48 */
49void
blueswir1511d2b12009-03-07 15:32:56 +000050if_output(struct socket *so, struct mbuf *ifm)
bellardf0cbd3e2004-04-22 00:10:48 +000051{
Jan Kiszka460fec62009-06-24 14:42:31 +020052 Slirp *slirp = ifm->slirp;
bellardf0cbd3e2004-04-22 00:10:48 +000053 struct mbuf *ifq;
54 int on_fastq = 1;
ths5fafdf22007-09-16 21:08:06 +000055
bellardf0cbd3e2004-04-22 00:10:48 +000056 DEBUG_CALL("if_output");
57 DEBUG_ARG("so = %lx", (long)so);
58 DEBUG_ARG("ifm = %lx", (long)ifm);
ths5fafdf22007-09-16 21:08:06 +000059
bellardf0cbd3e2004-04-22 00:10:48 +000060 /*
61 * First remove the mbuf from m_usedlist,
62 * since we're gonna use m_next and m_prev ourselves
63 * XXX Shouldn't need this, gotta change dtom() etc.
64 */
65 if (ifm->m_flags & M_USEDLIST) {
66 remque(ifm);
67 ifm->m_flags &= ~M_USEDLIST;
68 }
ths5fafdf22007-09-16 21:08:06 +000069
bellardf0cbd3e2004-04-22 00:10:48 +000070 /*
ths3b46e622007-09-17 08:09:54 +000071 * See if there's already a batchq list for this session.
bellardf0cbd3e2004-04-22 00:10:48 +000072 * This can include an interactive session, which should go on fastq,
73 * but gets too greedy... hence it'll be downgraded from fastq to batchq.
74 * We mustn't put this packet back on the fastq (or we'll send it out of order)
75 * XXX add cache here?
76 */
Jan Kiszka460fec62009-06-24 14:42:31 +020077 for (ifq = slirp->if_batchq.ifq_prev; ifq != &slirp->if_batchq;
78 ifq = ifq->ifq_prev) {
bellardf0cbd3e2004-04-22 00:10:48 +000079 if (so == ifq->ifq_so) {
80 /* A match! */
81 ifm->ifq_so = so;
82 ifs_insque(ifm, ifq->ifs_prev);
83 goto diddit;
84 }
85 }
ths5fafdf22007-09-16 21:08:06 +000086
bellardf0cbd3e2004-04-22 00:10:48 +000087 /* No match, check which queue to put it on */
88 if (so && (so->so_iptos & IPTOS_LOWDELAY)) {
Jan Kiszka460fec62009-06-24 14:42:31 +020089 ifq = slirp->if_fastq.ifq_prev;
bellardf0cbd3e2004-04-22 00:10:48 +000090 on_fastq = 1;
91 /*
92 * Check if this packet is a part of the last
93 * packet's session
94 */
95 if (ifq->ifq_so == so) {
96 ifm->ifq_so = so;
97 ifs_insque(ifm, ifq->ifs_prev);
98 goto diddit;
99 }
100 } else
Jan Kiszka460fec62009-06-24 14:42:31 +0200101 ifq = slirp->if_batchq.ifq_prev;
ths5fafdf22007-09-16 21:08:06 +0000102
bellardf0cbd3e2004-04-22 00:10:48 +0000103 /* Create a new doubly linked list for this session */
104 ifm->ifq_so = so;
105 ifs_init(ifm);
106 insque(ifm, ifq);
ths5fafdf22007-09-16 21:08:06 +0000107
bellardf0cbd3e2004-04-22 00:10:48 +0000108diddit:
Jan Kiszka460fec62009-06-24 14:42:31 +0200109 slirp->if_queued++;
ths5fafdf22007-09-16 21:08:06 +0000110
bellardf0cbd3e2004-04-22 00:10:48 +0000111 if (so) {
112 /* Update *_queued */
113 so->so_queued++;
114 so->so_nqueued++;
115 /*
116 * Check if the interactive session should be downgraded to
117 * the batchq. A session is downgraded if it has queued 6
118 * packets without pausing, and at least 3 of those packets
119 * have been sent over the link
120 * (XXX These are arbitrary numbers, probably not optimal..)
121 */
ths5fafdf22007-09-16 21:08:06 +0000122 if (on_fastq && ((so->so_nqueued >= 6) &&
bellardf0cbd3e2004-04-22 00:10:48 +0000123 (so->so_nqueued - so->so_queued) >= 3)) {
ths3b46e622007-09-17 08:09:54 +0000124
bellardf0cbd3e2004-04-22 00:10:48 +0000125 /* Remove from current queue... */
126 remque(ifm->ifs_next);
ths3b46e622007-09-17 08:09:54 +0000127
bellardf0cbd3e2004-04-22 00:10:48 +0000128 /* ...And insert in the new. That'll teach ya! */
Jan Kiszka460fec62009-06-24 14:42:31 +0200129 insque(ifm->ifs_next, &slirp->if_batchq);
bellardf0cbd3e2004-04-22 00:10:48 +0000130 }
131 }
132
133#ifndef FULL_BOLT
134 /*
135 * This prevents us from malloc()ing too many mbufs
136 */
Jan Kiszka460fec62009-06-24 14:42:31 +0200137 if_start(ifm->slirp);
bellardf0cbd3e2004-04-22 00:10:48 +0000138#endif
139}
140
141/*
142 * Send a packet
143 * We choose a packet based on it's position in the output queues;
144 * If there are packets on the fastq, they are sent FIFO, before
145 * everything else. Otherwise we choose the first packet from the
146 * batchq and send it. the next packet chosen will be from the session
147 * after this one, then the session after that one, and so on.. So,
148 * for example, if there are 3 ftp session's fighting for bandwidth,
149 * one packet will be sent from the first session, then one packet
150 * from the second session, then one packet from the third, then back
151 * to the first, etc. etc.
152 */
153void
Jan Kiszka460fec62009-06-24 14:42:31 +0200154if_start(Slirp *slirp)
bellardf0cbd3e2004-04-22 00:10:48 +0000155{
156 struct mbuf *ifm, *ifqt;
ths5fafdf22007-09-16 21:08:06 +0000157
bellardf0cbd3e2004-04-22 00:10:48 +0000158 DEBUG_CALL("if_start");
ths5fafdf22007-09-16 21:08:06 +0000159
Jan Kiszka460fec62009-06-24 14:42:31 +0200160 if (slirp->if_queued == 0)
bellardf0cbd3e2004-04-22 00:10:48 +0000161 return; /* Nothing to do */
ths5fafdf22007-09-16 21:08:06 +0000162
bellardf0cbd3e2004-04-22 00:10:48 +0000163 again:
164 /* check if we can really output */
Jan Kiszka9f8bd042009-06-24 14:42:31 +0200165 if (!slirp_can_output(slirp->opaque))
bellardf0cbd3e2004-04-22 00:10:48 +0000166 return;
167
168 /*
169 * See which queue to get next packet from
170 * If there's something in the fastq, select it immediately
171 */
Jan Kiszka460fec62009-06-24 14:42:31 +0200172 if (slirp->if_fastq.ifq_next != &slirp->if_fastq) {
173 ifm = slirp->if_fastq.ifq_next;
bellardf0cbd3e2004-04-22 00:10:48 +0000174 } else {
175 /* Nothing on fastq, see if next_m is valid */
Jan Kiszka460fec62009-06-24 14:42:31 +0200176 if (slirp->next_m != &slirp->if_batchq)
177 ifm = slirp->next_m;
bellardf0cbd3e2004-04-22 00:10:48 +0000178 else
Jan Kiszka460fec62009-06-24 14:42:31 +0200179 ifm = slirp->if_batchq.ifq_next;
ths3b46e622007-09-17 08:09:54 +0000180
bellardf0cbd3e2004-04-22 00:10:48 +0000181 /* Set which packet to send on next iteration */
Jan Kiszka460fec62009-06-24 14:42:31 +0200182 slirp->next_m = ifm->ifq_next;
bellardf0cbd3e2004-04-22 00:10:48 +0000183 }
184 /* Remove it from the queue */
185 ifqt = ifm->ifq_prev;
186 remque(ifm);
Jan Kiszka460fec62009-06-24 14:42:31 +0200187 slirp->if_queued--;
ths5fafdf22007-09-16 21:08:06 +0000188
bellardf0cbd3e2004-04-22 00:10:48 +0000189 /* If there are more packets for this session, re-queue them */
190 if (ifm->ifs_next != /* ifm->ifs_prev != */ ifm) {
191 insque(ifm->ifs_next, ifqt);
192 ifs_remque(ifm);
193 }
ths5fafdf22007-09-16 21:08:06 +0000194
bellardf0cbd3e2004-04-22 00:10:48 +0000195 /* Update so_queued */
196 if (ifm->ifq_so) {
197 if (--ifm->ifq_so->so_queued == 0)
198 /* If there's no more queued, reset nqueued */
199 ifm->ifq_so->so_nqueued = 0;
200 }
ths5fafdf22007-09-16 21:08:06 +0000201
bellardf0cbd3e2004-04-22 00:10:48 +0000202 /* Encapsulate the packet for sending */
Jan Kiszka460fec62009-06-24 14:42:31 +0200203 if_encap(slirp, (uint8_t *)ifm->m_data, ifm->m_len);
bellardf0cbd3e2004-04-22 00:10:48 +0000204
bellardc9a62112004-09-13 21:42:51 +0000205 m_free(ifm);
206
Jan Kiszka460fec62009-06-24 14:42:31 +0200207 if (slirp->if_queued)
bellardf0cbd3e2004-04-22 00:10:48 +0000208 goto again;
209}