/* * Copyright (c) 1995 Danny Gasparovski. * * Please read the file COPYRIGHT for the * terms and conditions of the copyright. */#include "slirp.h"int if_mtu, if_mru;int if_comp;int if_maxlinkhdr;int     if_queued = 0;                  /* Number of packets queued so far */int     if_thresh = 10;                 /* Number of packets queued before we start sending					 * (to prevent allocing too many mbufs) */struct  mbuf if_fastq;                  /* fast queue (for interactive data) */struct  mbuf if_batchq;                 /* queue for non-interactive data */struct	mbuf *next_m;			/* Pointer to next mbuf to output */#define ifs_init(ifm) ((ifm)->ifs_next = (ifm)->ifs_prev = (ifm))voidifs_insque(ifm, ifmhead)	struct mbuf *ifm, *ifmhead;{	ifm->ifs_next = ifmhead->ifs_next;	ifmhead->ifs_next = ifm;	ifm->ifs_prev = ifmhead;	ifm->ifs_next->ifs_prev = ifm;}voidifs_remque(ifm)	struct mbuf *ifm;{	ifm->ifs_prev->ifs_next = ifm->ifs_next;	ifm->ifs_next->ifs_prev = ifm->ifs_prev;}voidif_init(){#if 0	/*	 * Set if_maxlinkhdr to 48 because it's 40 bytes for TCP/IP,	 * and 8 bytes for PPP, but need to have it on an 8byte boundary	 */#ifdef USE_PPP	if_maxlinkhdr = 48;#else	if_maxlinkhdr = 40;#endif#else        /* 2 for alignment, 14 for ethernet, 40 for TCP/IP */        if_maxlinkhdr = 2 + 14 + 40;#endif	if_mtu = 1500;	if_mru = 1500;	if_comp = IF_AUTOCOMP;	if_fastq.ifq_next = if_fastq.ifq_prev = &if_fastq;	if_batchq.ifq_next = if_batchq.ifq_prev = &if_batchq;        //	sl_compress_init(&comp_s);	next_m = &if_batchq;}#if 0/* * This shouldn't be needed since the modem is blocking and * we don't expect any signals, but what the hell.. */inline intwriten(fd, bptr, n)	int fd;	char *bptr;	int n;{	int ret;	int total;		/* This should succeed most of the time */	ret = send(fd, bptr, n,0);	if (ret == n || ret <= 0)	   return ret;		/* Didn't write everything, go into the loop */	total = ret;	while (n > total) {		ret = send(fd, bptr+total, n-total,0);		if (ret <= 0)		   return ret;		total += ret;	}	return total;}/* * if_input - read() the tty, do "top level" processing (ie: check for any escapes), * and pass onto (*ttyp->if_input) *  * XXXXX Any zeros arriving by themselves are NOT placed into the arriving packet. */#define INBUFF_SIZE 2048 /* XXX */voidif_input(ttyp)	struct ttys *ttyp;{	u_char if_inbuff[INBUFF_SIZE];	int if_n;		DEBUG_CALL("if_input");	DEBUG_ARG("ttyp = %lx", (long)ttyp);		if_n = recv(ttyp->fd, (char *)if_inbuff, INBUFF_SIZE,0);		DEBUG_MISC((dfd, " read %d bytes\n", if_n));		if (if_n <= 0) {		if (if_n == 0 || (errno != EINTR && errno != EAGAIN)) {			if (ttyp->up)			   link_up--;			tty_detached(ttyp, 0);		}		return;	}	if (if_n == 1) {		if (*if_inbuff == '0') {			ttyp->ones = 0;			if (++ttyp->zeros >= 5)			   slirp_exit(0);			return;		}		if (*if_inbuff == '1') {			ttyp->zeros = 0;			if (++ttyp->ones >= 5)			   tty_detached(ttyp, 0);			return;		}	}	ttyp->ones = ttyp->zeros = 0;		(*ttyp->if_input)(ttyp, if_inbuff, if_n);}#endif		/* * if_output: Queue packet into an output queue. * There are 2 output queue's, if_fastq and if_batchq.  * Each output queue is a doubly linked list of double linked lists * of mbufs, each list belonging to one "session" (socket).  This * way, we can output packets fairly by sending one packet from each * session, instead of all the packets from one session, then all packets * from the next session, etc.  Packets on the if_fastq get absolute  * priority, but if one session hogs the link, it gets "downgraded" * to the batchq until it runs out of packets, then it'll return * to the fastq (eg. if the user does an ls -alR in a telnet session, * it'll temporarily get downgraded to the batchq) */voidif_output(so, ifm)	struct socket *so;	struct mbuf *ifm;{	struct mbuf *ifq;	int on_fastq = 1;		DEBUG_CALL("if_output");	DEBUG_ARG("so = %lx", (long)so);	DEBUG_ARG("ifm = %lx", (long)ifm);		/*	 * First remove the mbuf from m_usedlist,	 * since we're gonna use m_next and m_prev ourselves	 * XXX Shouldn't need this, gotta change dtom() etc.	 */	if (ifm->m_flags & M_USEDLIST) {		remque(ifm);		ifm->m_flags &= ~M_USEDLIST;	}		/*	 * See if there's already a batchq list for this session.  	 * This can include an interactive session, which should go on fastq,	 * but gets too greedy... hence it'll be downgraded from fastq to batchq.	 * We mustn't put this packet back on the fastq (or we'll send it out of order)	 * XXX add cache here?	 */	for (ifq = if_batchq.ifq_prev; ifq != &if_batchq; ifq = ifq->ifq_prev) {		if (so == ifq->ifq_so) {			/* A match! */			ifm->ifq_so = so;			ifs_insque(ifm, ifq->ifs_prev);			goto diddit;		}	}		/* No match, check which queue to put it on */	if (so && (so->so_iptos & IPTOS_LOWDELAY)) {		ifq = if_fastq.ifq_prev;		on_fastq = 1;		/*		 * Check if this packet is a part of the last		 * packet's session		 */		if (ifq->ifq_so == so) {			ifm->ifq_so = so;			ifs_insque(ifm, ifq->ifs_prev);			goto diddit;		}	} else		ifq = if_batchq.ifq_prev;		/* Create a new doubly linked list for this session */	ifm->ifq_so = so;	ifs_init(ifm);	insque(ifm, ifq);	diddit:	++if_queued;		if (so) {		/* Update *_queued */		so->so_queued++;		so->so_nqueued++;		/*		 * Check if the interactive session should be downgraded to		 * the batchq.  A session is downgraded if it has queued 6		 * packets without pausing, and at least 3 of those packets		 * have been sent over the link		 * (XXX These are arbitrary numbers, probably not optimal..)		 */		if (on_fastq && ((so->so_nqueued >= 6) && 				 (so->so_nqueued - so->so_queued) >= 3)) {						/* Remove from current queue... */			remque(ifm->ifs_next);						/* ...And insert in the new.  That'll teach ya! */			insque(ifm->ifs_next, &if_batchq);		}	}#ifndef FULL_BOLT	/*	 * This prevents us from malloc()ing too many mbufs	 */	if (link_up) {		/* if_start will check towrite */		if_start();	}#endif}/* * Send a packet * We choose a packet based on it's position in the output queues; * If there are packets on the fastq, they are sent FIFO, before * everything else.  Otherwise we choose the first packet from the * batchq and send it.  the next packet chosen will be from the session * after this one, then the session after that one, and so on..  So, * for example, if there are 3 ftp session's fighting for bandwidth, * one packet will be sent from the first session, then one packet * from the second session, then one packet from the third, then back * to the first, etc. etc. */voidif_start(void){	struct mbuf *ifm, *ifqt;		DEBUG_CALL("if_start");		if (if_queued == 0)	   return; /* Nothing to do */	 again:        /* check if we can really output */        if (!slirp_can_output())            return;	/*	 * See which queue to get next packet from	 * If there's something in the fastq, select it immediately	 */	if (if_fastq.ifq_next != &if_fastq) {		ifm = if_fastq.ifq_next;	} else {		/* Nothing on fastq, see if next_m is valid */		if (next_m != &if_batchq)		   ifm = next_m;		else		   ifm = if_batchq.ifq_next;				/* Set which packet to send on next iteration */		next_m = ifm->ifq_next;	}	/* Remove it from the queue */	ifqt = ifm->ifq_prev;	remque(ifm);	--if_queued;		/* If there are more packets for this session, re-queue them */	if (ifm->ifs_next != /* ifm->ifs_prev != */ ifm) {		insque(ifm->ifs_next, ifqt);		ifs_remque(ifm);	}		/* Update so_queued */	if (ifm->ifq_so) {		if (--ifm->ifq_so->so_queued == 0)		   /* If there's no more queued, reset nqueued */		   ifm->ifq_so->so_nqueued = 0;	}		/* Encapsulate the packet for sending */        if_encap((const uint8_t *)ifm->m_data, ifm->m_len);        m_free(ifm);	if (if_queued)	   goto again;}