socket.c

一个Windows下的Linux专用虚拟机

/*
 * Copyright (c) 1995 Danny Gasparovski.
 * 
 * Please read the file COPYRIGHT for the 
 * terms and conditions of the copyright.
 */

#define WANT_SYS_IOCTL_H
#include "slirp.h"
#include "ip_icmp.h"
#include "main.h"

void
so_init()
{
	/* Nothing yet */
}


struct socket *
solookup(head, laddr, lport, faddr, fport)
	struct socket *head;
	struct in_addr laddr;
	u_int lport;
	struct in_addr faddr;
	u_int fport;
{
	struct socket *so;
	
	for (so = head->so_next; so != head; so = so->so_next) {
		if (so->so_lport == lport && 
		    so->so_laddr.s_addr == laddr.s_addr &&
		    so->so_faddr.s_addr == faddr.s_addr &&
		    so->so_fport == fport)
		   break;
	}
	
	if (so == head)
	   return (struct socket *)NULL;
	return so;
	
}

/*
 * Create a new socket, initialise the fields
 * It is the responsibility of the caller to
 * insque() it into the correct linked-list
 */
struct socket *
socreate()
{
  struct socket *so;
	
  so = (struct socket *)malloc(sizeof(struct socket));
  if(so) {
    memset(so, 0, sizeof(struct socket));
    so->so_state = SS_NOFDREF;
    so->s = -1;
  }
  return(so);
}

/*
 * remque and free a socket, clobber cache
 */
void
sofree(so)
	struct socket *so;
{
  if (so->so_emu==EMU_RSH && so->extra) {
	sofree(so->extra);
	so->extra=NULL;
  }
  if (so == tcp_last_so)
    tcp_last_so = &tcb;
  else if (so == udp_last_so)
    udp_last_so = &udb;
	
  m_free(so->so_m);
	
  if(so->so_next && so->so_prev) 
    remque(so);  /* crashes if so is not in a queue */

  free(so);
}

/*
 * Read from so's socket into sb_snd, updating all relevant sbuf fields
 * NOTE: This will only be called if it is select()ed for reading, so
 * a read() of 0 (or less) means it's disconnected
 */
int
soread(so)
	struct socket *so;
{
	int n, nn, lss, total;
	struct sbuf *sb = &so->so_snd;
	int len = sb->sb_datalen - sb->sb_cc;
	struct iovec iov[2] = { {0}, };
	int mss = so->so_tcpcb->t_maxseg;
	
	DEBUG_CALL("soread");
	DEBUG_ARG("so = %lx", (long )so);
	
	/* 
	 * No need to check if there's enough room to read.
	 * soread wouldn't have been called if there weren't
	 */
	
	len = sb->sb_datalen - sb->sb_cc;
	
	iov[0].iov_base = sb->sb_wptr;
	if (sb->sb_wptr < sb->sb_rptr) {
		iov[0].iov_len = sb->sb_rptr - sb->sb_wptr;
		/* Should never succeed, but... */
		if (iov[0].iov_len > len)
		   iov[0].iov_len = len;
		if (iov[0].iov_len > mss)
		   iov[0].iov_len -= iov[0].iov_len%mss;
		n = 1;
	} else {
		iov[0].iov_len = (sb->sb_data + sb->sb_datalen) - sb->sb_wptr;
		/* Should never succeed, but... */
		if (iov[0].iov_len > len) iov[0].iov_len = len;
		len -= iov[0].iov_len;
		if (len) {
			iov[1].iov_base = sb->sb_data;
			iov[1].iov_len = sb->sb_rptr - sb->sb_data;
			if(iov[1].iov_len > len)
			   iov[1].iov_len = len;
			total = iov[0].iov_len + iov[1].iov_len;
			if (total > mss) {
				lss = total%mss;
				if (iov[1].iov_len > lss) {
					iov[1].iov_len -= lss;
					n = 2;
				} else {
					lss -= iov[1].iov_len;
					iov[0].iov_len -= lss;
					n = 1;
				}
			} else
				n = 2;
		} else {
			if (iov[0].iov_len > mss)
			   iov[0].iov_len -= iov[0].iov_len%mss;
			n = 1;
		}
	}
	
#ifdef HAVE_READV
	nn = readv(so->s, (struct iovec *)iov, n);
	DEBUG_MISC((dfd, " ... read nn = %d bytes\n", nn));
#else
	nn = recv(so->s, iov[0].iov_base, iov[0].iov_len,0);
#endif	
	if (nn <= 0) {
		if (nn < 0 && (errno == EINTR || errno == EAGAIN))
			return 0;
		else {
			DEBUG_MISC((dfd, " --- soread() disconnected, nn = %d, errno = %d-%s\n", nn, errno,strerror(errno)));
			sofcantrcvmore(so);
			tcp_sockclosed(sototcpcb(so));
			return -1;
		}
	}
	
#ifndef HAVE_READV
	/*
	 * If there was no error, try and read the second time round
	 * We read again if n = 2 (ie, there's another part of the buffer)
	 * and we read as much as we could in the first read
	 * We don't test for <= 0 this time, because there legitimately
	 * might not be any more data (since the socket is non-blocking),
	 * a close will be detected on next iteration.
	 * A return of -1 wont (shouldn't) happen, since it didn't happen above
	 *
	 * Dan Aloni says: actually it can return -1 here...
	 */
	if (n == 2 && nn == iov[0].iov_len) {
            int ret;
            ret = recv(so->s, iov[1].iov_base, iov[1].iov_len,0);
            if (ret > 0)
                nn += ret;
        }
	
	DEBUG_MISC((dfd, " ... read nn = %d bytes\n", nn));
#endif
	
	/* Update fields */
	sb->sb_cc += nn;
	sb->sb_wptr += nn;
	if (sb->sb_wptr >= (sb->sb_data + sb->sb_datalen))
		sb->sb_wptr -= sb->sb_datalen;
	return nn;
}
	
/*
 * Get urgent data
 * 
 * When the socket is created, we set it SO_OOBINLINE,
 * so when OOB data arrives, we soread() it and everything
 * in the send buffer is sent as urgent data
 */
void
sorecvoob(so)
	struct socket *so;
{
	struct tcpcb *tp = sototcpcb(so);

	DEBUG_CALL("sorecvoob");
	DEBUG_ARG("so = %lx", (long)so);
	
	/*
	 * We take a guess at how much urgent data has arrived.
	 * In most situations, when urgent data arrives, the next
	 * read() should get all the urgent data.  This guess will
	 * be wrong however if more data arrives just after the
	 * urgent data, or the read() doesn't return all the 
	 * urgent data.
	 */
	soread(so);
	tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
	tp->t_force = 1;
	tcp_output(tp);
	tp->t_force = 0;
}

/*
 * Send urgent data
 * There's a lot duplicated code here, but...
 */
int
sosendoob(so)
	struct socket *so;
{
	struct sbuf *sb = &so->so_rcv;
	char buff[2048]; /* XXX Shouldn't be sending more oob data than this */
	
	int n, len;
	
	DEBUG_CALL("sosendoob");
	DEBUG_ARG("so = %lx", (long)so);
	DEBUG_ARG("sb->sb_cc = %d", sb->sb_cc);
	
	if (so->so_urgc > 2048)
	   so->so_urgc = 2048; /* XXXX */
	
	if (sb->sb_rptr < sb->sb_wptr) {
		/* We can send it directly */
		n = send(so->s, sb->sb_rptr, so->so_urgc, (MSG_OOB)); /* |MSG_DONTWAIT)); */
		so->so_urgc -= n;
		
		DEBUG_MISC((dfd, " --- sent %d bytes urgent data, %d urgent bytes left\n", n, so->so_urgc));
	} else {
		/* 
		 * Since there's no sendv or sendtov like writev,
		 * we must copy all data to a linear buffer then
		 * send it all
		 */
		len = (sb->sb_data + sb->sb_datalen) - sb->sb_rptr;
		if (len > so->so_urgc) len = so->so_urgc;
		memcpy(buff, sb->sb_rptr, len);
		so->so_urgc -= len;
		if (so->so_urgc) {
			n = sb->sb_wptr - sb->sb_data;
			if (n > so->so_urgc) n = so->so_urgc;
			memcpy((buff + len), sb->sb_data, n);
			so->so_urgc -= n;
			len += n;
		}
		n = send(so->s, buff, len, (MSG_OOB)); /* |MSG_DONTWAIT)); */
#ifdef DEBUG
		if (n != len)
		   DEBUG_ERROR((dfd, "Didn't send all data urgently XXXXX\n"));
#endif		
		DEBUG_MISC((dfd, " ---2 sent %d bytes urgent data, %d urgent bytes left\n", n, so->so_urgc));
	}
	
	sb->sb_cc -= n;
	sb->sb_rptr += n;
	if (sb->sb_rptr >= (sb->sb_data + sb->sb_datalen))
		sb->sb_rptr -= sb->sb_datalen;
	
	return n;
}

/*
 * Write data from so_rcv to so's socket, 
 * updating all sbuf field as necessary
 */
int
sowrite(so)
	struct socket *so;
{
	int  n,nn;
	struct sbuf *sb = &so->so_rcv;
	int len = sb->sb_cc;
	struct iovec iov[2] = { {0}, };
	
	DEBUG_CALL("sowrite");
	DEBUG_ARG("so = %lx", (long)so);
	
	if (so->so_urgc) {
		sosendoob(so);
		if (sb->sb_cc == 0)
			return 0;
	}

	/*
	 * No need to check if there's something to write,
	 * sowrite wouldn't have been called otherwise
	 */
	
        len = sb->sb_cc;
	
	iov[0].iov_base = sb->sb_rptr;
	if (sb->sb_rptr < sb->sb_wptr) {
		iov[0].iov_len = sb->sb_wptr - sb->sb_rptr;
		/* Should never succeed, but... */
		if (iov[0].iov_len > len) iov[0].iov_len = len;
		n = 1;
	} else {
		iov[0].iov_len = (sb->sb_data + sb->sb_datalen) - sb->sb_rptr;
		if (iov[0].iov_len > len) iov[0].iov_len = len;
		len -= iov[0].iov_len;
		if (len) {
			iov[1].iov_base = sb->sb_data;
			iov[1].iov_len = sb->sb_wptr - sb->sb_data;
			if (iov[1].iov_len > len) iov[1].iov_len = len;
			n = 2;
		} else
			n = 1;
	}
	/* Check if there's urgent data to send, and if so, send it */

#ifdef HAVE_READV
	nn = writev(so->s, (const struct iovec *)iov, n);
	
	DEBUG_MISC((dfd, "  ... wrote nn = %d bytes\n", nn));
#else
	nn = send(so->s, iov[0].iov_base, iov[0].iov_len,0);
#endif
	/* This should never happen, but people tell me it does *shrug* */
	if (nn < 0 && (errno == EAGAIN || errno == EINTR))
		return 0;
	
	if (nn <= 0) {
		DEBUG_MISC((dfd, " --- sowrite disconnected, so->so_state = %x, errno = %d\n",
			so->so_state, errno));
		sofcantsendmore(so);
		tcp_sockclosed(sototcpcb(so));
		return -1;
	}
	
#ifndef HAVE_READV
	if (n == 2 && nn == iov[0].iov_len) {
            int ret;
            ret = send(so->s, iov[1].iov_base, iov[1].iov_len,0);
            if (ret > 0)
                nn += ret;
        }
        DEBUG_MISC((dfd, "  ... wrote nn = %d bytes\n", nn));
#endif
	
	/* Update sbuf */
	sb->sb_cc -= nn;