/*
 * 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"
#ifdef __sun__
#include <sys/filio.h>
#endif

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(PNATState pData, struct socket *so)
{
  if (so->so_emu==EMU_RSH && so->extra) {
        sofree(pData, 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(pData, so->so_m);


  if(so->so_next && so->so_prev)
    remque(pData, 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(PNATState pData, 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];
        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;
        iov[1].iov_base = 0;
        iov[1].iov_len  = 0;
        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(pData, 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
         */
        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(PNATState pData, 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(pData, so);
        tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
        tp->t_force = 1;
        tcp_output(pData, 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(PNATState pData, struct socket *so)
{
        int  n,nn;
        struct sbuf *sb = &so->so_rcv;
        int len = sb->sb_cc;
        struct iovec iov[2];

        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;
        iov[1].iov_base = 0;
        iov[1].iov_len  = 0;
        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(pData, 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;
        sb->sb_rptr += nn;
        if (sb->sb_rptr >= (sb->sb_data + sb->sb_datalen))
                sb->sb_rptr -= sb->sb_datalen;

        /*
         * If in DRAIN mode, and there's no more data, set
         * it CANTSENDMORE
         */
        if ((so->so_state & SS_FWDRAIN) && sb->sb_cc == 0)
                sofcantsendmore(so);

        return nn;
}

/*
 * recvfrom() a UDP socket
 */
void
sorecvfrom(PNATState pData, struct socket *so)
{
        struct sockaddr_in addr;
        socklen_t addrlen = sizeof(struct sockaddr_in);

        DEBUG_CALL("sorecvfrom");
        DEBUG_ARG("so = %lx", (long)so);

        if (so->so_type == IPPROTO_ICMP) {   /* This is a "ping" reply */
          char buff[256];
          int len;

          len = recvfrom(so->s, buff, 256, 0,
                         (struct sockaddr *)&addr, &addrlen);
          /* XXX Check if reply is "correct"? */

          if(len == -1 || len == 0) {
            u_char code=ICMP_UNREACH_PORT;

            if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
            else if(errno == ENETUNREACH) code=ICMP_UNREACH_NET;

            DEBUG_MISC((dfd," udp icmp rx errno = %d-%s\n",
                        errno,strerror(errno)));
            icmp_error(pData, so->so_m, ICMP_UNREACH,code, 0,strerror(errno));
          } else {
            icmp_reflect(pData, so->so_m);
            so->so_m = 0; /* Don't m_free() it again! */
          }
          /* No need for this socket anymore, udp_detach it */
          udp_detach(pData, so);
        } else {                                /* A "normal" UDP packet */
          struct mbuf *m;
          int len, n;

          if (!(m = m_get(pData))) return;
          m->m_data += if_maxlinkhdr;

          /*
           * XXX Shouldn't FIONREAD packets destined for port 53,
           * but I don't know the max packet size for DNS lookups
           */
          len = M_FREEROOM(m);
          /* if (so->so_fport != htons(53)) { */
          ioctlsocket(so->s, FIONREAD, &n);

          if (n > len) {
            n = (m->m_data - m->m_dat) + m->m_len + n + 1;
            m_inc(m, n);
            len = M_FREEROOM(m);
          }
          /* } */

          m->m_len = recvfrom(so->s, m->m_data, len, 0,
                              (struct sockaddr *)&addr, &addrlen);
          DEBUG_MISC((dfd, " did recvfrom %d, errno = %d-%s\n",
                      m->m_len, errno,strerror(errno)));
          if(m->m_len<0) {
            u_char code=ICMP_UNREACH_PORT;

            if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
            else if(errno == ENETUNREACH) code=ICMP_UNREACH_NET;

            DEBUG_MISC((dfd," rx error, tx icmp ICMP_UNREACH:%i\n", code));
            icmp_error(pData, so->so_m, ICMP_UNREACH,code, 0,strerror(errno));
            m_free(pData, m);
          } else {
          /*
           * Hack: domain name lookup will be used the most for UDP,
           * and since they'll only be used once there's no need
           * for the 4 minute (or whatever) timeout... So we time them
           * out much quicker (10 seconds  for now...)
           */
            if (so->so_expire) {
              if (so->so_fport == htons(53))
                so->so_expire = curtime + SO_EXPIREFAST;
              else
                so->so_expire = curtime + SO_EXPIRE;
            }

            /*          if (m->m_len == len) {
             *                  m_inc(m, MINCSIZE);
             *                  m->m_len = 0;
             *          }
             */

            /*
             * If this packet was destined for CTL_ADDR,
             * make it look like that's where it came from, done by udp_output
             */
            udp_output(pData, so, m, &addr);
          } /* rx error */
        } /* if ping packet */
}

/*
 * sendto() a socket
 */
int
sosendto(PNATState pData, struct socket *so, struct mbuf *m)
{
        int ret;
        struct sockaddr_in addr;
#if 0
        struct sockaddr_in host_addr;
#endif

        DEBUG_CALL("sosendto");
        DEBUG_ARG("so = %lx", (long)so);
        DEBUG_ARG("m = %lx", (long)m);

        addr.sin_family = AF_INET;
        if ((so->so_faddr.s_addr & htonl(pData->netmask)) == special_addr.s_addr) {
          /* It's an alias */
          uint32_t last_byte = ntohl(so->so_faddr.s_addr) & ~pData->netmask;
          switch(last_byte) {
#if 0
          /* handle this case at 'default:' */
          case CTL_BROADCAST:
            addr.sin_addr.s_addr = INADDR_BROADCAST;
# if 0
            /* Send the packet to host to fully emulate broadcast */
            /** @todo r=klaus: on Linux host this causes the host to receive
             * the packet twice for some reason. And I cannot find any place
             * in the man pages which states that sending a broadcast does not
             * reach the host itself. */
            host_addr.sin_family = AF_INET;
            host_addr.sin_port = so->so_fport;
            host_addr.sin_addr = our_addr;
            sendto(so->s, m->m_data, m->m_len, 0,
                  (struct sockaddr *)&host_addr, sizeof (struct sockaddr));
# endif
            break;
#endif
          case CTL_DNS:
            if (!get_dns_addr(pData, &dns_addr))
                addr.sin_addr = dns_addr;
            else
                addr.sin_addr = loopback_addr;
            break;
          case CTL_ALIAS:
          default:
            if (last_byte == ~pData->netmask)
              addr.sin_addr.s_addr = INADDR_BROADCAST;
            else
              addr.sin_addr = loopback_addr;
            break;
          }
        } else
          addr.sin_addr = so->so_faddr;
        addr.sin_port = so->so_fport;

        DEBUG_MISC((dfd, " sendto()ing, addr.sin_port=%d, addr.sin_addr.s_addr=%.16s\n", ntohs(addr.sin_port), inet_ntoa(addr.sin_addr)));

        /* Don't care what port we get */
        ret = sendto(so->s, m->m_data, m->m_len, 0,
                     (struct sockaddr *)&addr, sizeof (struct sockaddr));
        if (ret < 0)
                return -1;

        /*
         * Kill the socket if there's no reply in 4 minutes,
         * but only if it's an expirable socket
         */
        if (so->so_expire)
                so->so_expire = curtime + SO_EXPIRE;
        so->so_state = SS_ISFCONNECTED; /* So that it gets select()ed */
        return 0;
}

/*
 * XXX This should really be tcp_listen
 */
struct socket *
solisten(PNATState pData, u_int port, u_int32_t laddr, u_int lport, int flags)
{
        struct sockaddr_in addr;
        struct socket *so;
        socklen_t addrlen = sizeof(addr);
        int s, opt = 1;

        DEBUG_CALL("solisten");
        DEBUG_ARG("port = %d", port);
        DEBUG_ARG("laddr = %x", laddr);
        DEBUG_ARG("lport = %d", lport);
        DEBUG_ARG("flags = %x", flags);

        if ((so = socreate()) == NULL) {
          /* free(so);      Not sofree() ??? free(NULL) == NOP */
          return NULL;
        }

        /* Don't tcp_attach... we don't need so_snd nor so_rcv */
        if ((so->so_tcpcb = tcp_newtcpcb(pData, so)) == NULL) {
                free(so);
                return NULL;
        }
        insque(pData, so,&tcb);

        /*
         * SS_FACCEPTONCE sockets must time out.
         */
        if (flags & SS_FACCEPTONCE)
           so->so_tcpcb->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT*2;

        so->so_state = (SS_FACCEPTCONN|flags);
        so->so_lport = lport; /* Kept in network format */
        so->so_laddr.s_addr = laddr; /* Ditto */

        addr.sin_family = AF_INET;
        addr.sin_addr.s_addr = INADDR_ANY;
        addr.sin_port = port;

        if (((s = socket(AF_INET,SOCK_STREAM,0)) < 0) ||
            (setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int)) < 0) ||
            (bind(s,(struct sockaddr *)&addr, sizeof(addr)) < 0) ||
            (listen(s,1) < 0)) {
#ifdef RT_OS_WINDOWS
                int tmperrno = WSAGetLastError(); /* Don't clobber the real reason we failed */
                closesocket(s);
                sofree(pData, so);
                /* Restore the real errno */
                WSASetLastError(tmperrno);
#else
                int tmperrno = errno; /* Don't clobber the real reason we failed */
                close(s);
                sofree(pData, so);
                /* Restore the real errno */
                errno = tmperrno;
#endif
                return NULL;
        }
        setsockopt(s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int));

        getsockname(s,(struct sockaddr *)&addr,&addrlen);
        so->so_fport = addr.sin_port;
        if (addr.sin_addr.s_addr == 0 || addr.sin_addr.s_addr == loopback_addr.s_addr)
           so->so_faddr = alias_addr;
        else
           so->so_faddr = addr.sin_addr;

        so->s = s;
        return so;
}

/*
 * Data is available in so_rcv
 * Just write() the data to the socket
 * XXX not yet...
 */
void
sorwakeup(so)
        struct socket *so;
{
/*      sowrite(so); */
/*      FD_CLR(so->s,&writefds); */
}

/*
 * Data has been freed in so_snd
 * We have room for a read() if we want to
 * For now, don't read, it'll be done in the main loop
 */
void
sowwakeup(so)
        struct socket *so;
{
        /* Nothing, yet */
}

/*
 * Various session state calls
 * XXX Should be #define's
 * The socket state stuff needs work, these often get call 2 or 3
 * times each when only 1 was needed
 */
void
soisfconnecting(so)
        register struct socket *so;
{
        so->so_state &= ~(SS_NOFDREF|SS_ISFCONNECTED|SS_FCANTRCVMORE|
                          SS_FCANTSENDMORE|SS_FWDRAIN);
        so->so_state |= SS_ISFCONNECTING; /* Clobber other states */
}

void
soisfconnected(so)
        register struct socket *so;
{
        so->so_state &= ~(SS_ISFCONNECTING|SS_FWDRAIN|SS_NOFDREF);
        so->so_state |= SS_ISFCONNECTED; /* Clobber other states */
}

void
sofcantrcvmore(so)
        struct  socket *so;
{
        if ((so->so_state & SS_NOFDREF) == 0) {
                shutdown(so->s,0);
        }
        so->so_state &= ~(SS_ISFCONNECTING);
        if (so->so_state & SS_FCANTSENDMORE)
           so->so_state = SS_NOFDREF; /* Don't select it */ /* XXX close() here as well? */
        else
           so->so_state |= SS_FCANTRCVMORE;
}

void
sofcantsendmore(so)
        struct socket *so;
{
        if ((so->so_state & SS_NOFDREF) == 0) {
            shutdown(so->s,1);           /* send FIN to fhost */
        }
        so->so_state &= ~(SS_ISFCONNECTING);
        if (so->so_state & SS_FCANTRCVMORE)
           so->so_state = SS_NOFDREF; /* as above */
        else
           so->so_state |= SS_FCANTSENDMORE;
}

void
soisfdisconnected(so)
        struct socket *so;
{
/*      so->so_state &= ~(SS_ISFCONNECTING|SS_ISFCONNECTED); */
/*      close(so->s); */
/*      so->so_state = SS_ISFDISCONNECTED; */
        /*
         * XXX Do nothing ... ?
         */
}

/*
 * Set write drain mode
 * Set CANTSENDMORE once all data has been write()n
 */
void
sofwdrain(so)
        struct socket *so;
{
        if (so->so_rcv.sb_cc)
                so->so_state |= SS_FWDRAIN;
        else
                sofcantsendmore(so);
}