root / slirp / if.c @ 511d2b14
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/*
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* Copyright (c) 1995 Danny Gasparovski.
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*
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* Please read the file COPYRIGHT for the
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* terms and conditions of the copyright.
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*/
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#include <slirp.h> |
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int if_queued = 0; /* Number of packets queued so far */ |
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struct mbuf if_fastq; /* fast queue (for interactive data) */ |
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struct mbuf if_batchq; /* queue for non-interactive data */ |
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struct mbuf *next_m; /* Pointer to next mbuf to output */ |
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#define ifs_init(ifm) ((ifm)->ifs_next = (ifm)->ifs_prev = (ifm))
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static void |
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ifs_insque(struct mbuf *ifm, struct mbuf *ifmhead) |
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{ |
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ifm->ifs_next = ifmhead->ifs_next; |
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ifmhead->ifs_next = ifm; |
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ifm->ifs_prev = ifmhead; |
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ifm->ifs_next->ifs_prev = ifm; |
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} |
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static void |
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ifs_remque(struct mbuf *ifm)
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{ |
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ifm->ifs_prev->ifs_next = ifm->ifs_next; |
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ifm->ifs_next->ifs_prev = ifm->ifs_prev; |
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} |
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void
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if_init(void)
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{ |
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if_fastq.ifq_next = if_fastq.ifq_prev = &if_fastq; |
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if_batchq.ifq_next = if_batchq.ifq_prev = &if_batchq; |
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// sl_compress_init(&comp_s);
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next_m = &if_batchq; |
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} |
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#if 0
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/*
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* This shouldn't be needed since the modem is blocking and
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* we don't expect any signals, but what the hell..
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*/
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inline int
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writen(fd, bptr, n)
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int fd;
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char *bptr;
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int n;
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{
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int ret;
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int total;
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/* This should succeed most of the time */
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ret = send(fd, bptr, n,0);
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if (ret == n || ret <= 0)
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return ret;
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/* Didn't write everything, go into the loop */
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total = ret;
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while (n > total) {
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ret = send(fd, bptr+total, n-total,0);
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if (ret <= 0)
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return ret;
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total += ret;
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}
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return total;
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}
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/*
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* if_input - read() the tty, do "top level" processing (ie: check for any escapes),
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* and pass onto (*ttyp->if_input)
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*
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* XXXXX Any zeros arriving by themselves are NOT placed into the arriving packet.
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*/
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#define INBUFF_SIZE 2048 /* XXX */
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void
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if_input(ttyp)
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struct ttys *ttyp;
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{
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u_char if_inbuff[INBUFF_SIZE];
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int if_n;
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DEBUG_CALL("if_input");
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DEBUG_ARG("ttyp = %lx", (long)ttyp);
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if_n = recv(ttyp->fd, (char *)if_inbuff, INBUFF_SIZE,0);
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DEBUG_MISC((dfd, " read %d bytes\n", if_n));
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if (if_n <= 0) {
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if (if_n == 0 || (errno != EINTR && errno != EAGAIN)) {
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if (ttyp->up)
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link_up--;
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tty_detached(ttyp, 0);
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}
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return;
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}
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if (if_n == 1) {
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if (*if_inbuff == '0') {
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ttyp->ones = 0;
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if (++ttyp->zeros >= 5)
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slirp_exit(0);
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return;
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}
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if (*if_inbuff == '1') {
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ttyp->zeros = 0;
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if (++ttyp->ones >= 5)
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tty_detached(ttyp, 0);
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return;
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}
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}
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ttyp->ones = ttyp->zeros = 0;
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(*ttyp->if_input)(ttyp, if_inbuff, if_n);
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}
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#endif
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/*
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* if_output: Queue packet into an output queue.
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* There are 2 output queue's, if_fastq and if_batchq.
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* Each output queue is a doubly linked list of double linked lists
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* of mbufs, each list belonging to one "session" (socket). This
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* way, we can output packets fairly by sending one packet from each
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* session, instead of all the packets from one session, then all packets
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* from the next session, etc. Packets on the if_fastq get absolute
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* priority, but if one session hogs the link, it gets "downgraded"
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* to the batchq until it runs out of packets, then it'll return
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* to the fastq (eg. if the user does an ls -alR in a telnet session,
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* it'll temporarily get downgraded to the batchq)
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*/
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void
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if_output(struct socket *so, struct mbuf *ifm) |
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{ |
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struct mbuf *ifq;
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int on_fastq = 1; |
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DEBUG_CALL("if_output");
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DEBUG_ARG("so = %lx", (long)so); |
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DEBUG_ARG("ifm = %lx", (long)ifm); |
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/*
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* First remove the mbuf from m_usedlist,
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* since we're gonna use m_next and m_prev ourselves
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* XXX Shouldn't need this, gotta change dtom() etc.
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*/
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if (ifm->m_flags & M_USEDLIST) {
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remque(ifm); |
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ifm->m_flags &= ~M_USEDLIST; |
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} |
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/*
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* See if there's already a batchq list for this session.
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* This can include an interactive session, which should go on fastq,
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* but gets too greedy... hence it'll be downgraded from fastq to batchq.
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* We mustn't put this packet back on the fastq (or we'll send it out of order)
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* XXX add cache here?
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*/
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for (ifq = if_batchq.ifq_prev; ifq != &if_batchq; ifq = ifq->ifq_prev) {
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if (so == ifq->ifq_so) {
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/* A match! */
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ifm->ifq_so = so; |
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ifs_insque(ifm, ifq->ifs_prev); |
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goto diddit;
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} |
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} |
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/* No match, check which queue to put it on */
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if (so && (so->so_iptos & IPTOS_LOWDELAY)) {
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ifq = if_fastq.ifq_prev; |
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on_fastq = 1;
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/*
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* Check if this packet is a part of the last
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* packet's session
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*/
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if (ifq->ifq_so == so) {
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ifm->ifq_so = so; |
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ifs_insque(ifm, ifq->ifs_prev); |
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goto diddit;
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} |
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} else
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ifq = if_batchq.ifq_prev; |
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/* Create a new doubly linked list for this session */
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ifm->ifq_so = so; |
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ifs_init(ifm); |
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insque(ifm, ifq); |
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diddit:
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++if_queued; |
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if (so) {
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/* Update *_queued */
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so->so_queued++; |
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so->so_nqueued++; |
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/*
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* Check if the interactive session should be downgraded to
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* the batchq. A session is downgraded if it has queued 6
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* packets without pausing, and at least 3 of those packets
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* have been sent over the link
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* (XXX These are arbitrary numbers, probably not optimal..)
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*/
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if (on_fastq && ((so->so_nqueued >= 6) && |
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(so->so_nqueued - so->so_queued) >= 3)) {
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/* Remove from current queue... */
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remque(ifm->ifs_next); |
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/* ...And insert in the new. That'll teach ya! */
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insque(ifm->ifs_next, &if_batchq); |
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} |
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} |
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#ifndef FULL_BOLT
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/*
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* This prevents us from malloc()ing too many mbufs
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*/
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if (link_up) {
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/* if_start will check towrite */
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if_start(); |
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} |
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#endif
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} |
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/*
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* Send a packet
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* We choose a packet based on it's position in the output queues;
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* If there are packets on the fastq, they are sent FIFO, before
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* everything else. Otherwise we choose the first packet from the
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* batchq and send it. the next packet chosen will be from the session
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* after this one, then the session after that one, and so on.. So,
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* for example, if there are 3 ftp session's fighting for bandwidth,
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* one packet will be sent from the first session, then one packet
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* from the second session, then one packet from the third, then back
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* to the first, etc. etc.
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*/
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void
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if_start(void)
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{ |
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struct mbuf *ifm, *ifqt;
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DEBUG_CALL("if_start");
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if (if_queued == 0) |
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return; /* Nothing to do */ |
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again:
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/* check if we can really output */
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if (!slirp_can_output())
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return;
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/*
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* See which queue to get next packet from
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* If there's something in the fastq, select it immediately
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*/
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if (if_fastq.ifq_next != &if_fastq) {
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ifm = if_fastq.ifq_next; |
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} else {
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/* Nothing on fastq, see if next_m is valid */
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if (next_m != &if_batchq)
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ifm = next_m; |
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else
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ifm = if_batchq.ifq_next; |
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/* Set which packet to send on next iteration */
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next_m = ifm->ifq_next; |
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} |
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/* Remove it from the queue */
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ifqt = ifm->ifq_prev; |
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remque(ifm); |
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--if_queued; |
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/* If there are more packets for this session, re-queue them */
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if (ifm->ifs_next != /* ifm->ifs_prev != */ ifm) { |
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insque(ifm->ifs_next, ifqt); |
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ifs_remque(ifm); |
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} |
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/* Update so_queued */
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if (ifm->ifq_so) {
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if (--ifm->ifq_so->so_queued == 0) |
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/* If there's no more queued, reset nqueued */
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ifm->ifq_so->so_nqueued = 0;
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} |
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/* Encapsulate the packet for sending */
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if_encap((uint8_t *)ifm->m_data, ifm->m_len); |
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m_free(ifm); |
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if (if_queued)
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goto again;
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} |