vde-2/slirpvde/sbuf.c

   1 /*
   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 <config.h>
   9 #include <slirp.h>
  10
  11 /* Done as a macro in socket.h */
  12 /* int
  13  * sbspace(struct sockbuff *sb)
  14  * {
  15  *      return SB_DATALEN - sb->sb_cc;
  16  * }
  17  */
  18
  19 void
  20 sbfree(sb)
  21         struct sbuf *sb;
  22 {
  23         free(sb->sb_data);
  24 }
  25
  26 void
  27 sbdrop(sb, num)
  28         struct sbuf *sb;
  29         int num;
  30 {
  31         /*
  32          * We can only drop how much we have
  33          * This should never succeed
  34          */
  35         if(num > sb->sb_cc)
  36                 num = sb->sb_cc;
  37         sb->sb_cc -= num;
  38         sb->sb_rptr += num;
  39         if(sb->sb_rptr >= sb->sb_data + sb->sb_datalen)
  40                 sb->sb_rptr -= sb->sb_datalen;
  41
  42 }
  43
  44 void
  45 sbreserve(sb, size)
  46         struct sbuf *sb;
  47         int size;
  48 {
  49         if (sb->sb_data) {
  50                 /* Already alloced, realloc if necessary */
  51                 if (sb->sb_datalen != size) {
  52                         sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)realloc(sb->sb_data, size);
  53                         sb->sb_cc = 0;
  54                         if (sb->sb_wptr)
  55                            sb->sb_datalen = size;
  56                         else
  57                            sb->sb_datalen = 0;
  58                 }
  59         } else {
  60                 sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)malloc(size);
  61                 sb->sb_cc = 0;
  62                 if (sb->sb_wptr)
  63                    sb->sb_datalen = size;
  64                 else
  65                    sb->sb_datalen = 0;
  66         }
  67 }
  68
  69 /*
  70  * Try and write() to the socket, whatever doesn't get written
  71  * append to the buffer... for a host with a fast net connection,
  72  * this prevents an unnecessary copy of the data
  73  * (the socket is non-blocking, so we won't hang)
  74  */
  75 void
  76 sbappend(so, m)
  77         struct socket *so;
  78         struct mbuf *m;
  79 {
  80         int ret = 0;
  81
  82         DEBUG_CALL("sbappend");
  83         DEBUG_ARG("so = %lx", (long)so);
  84         DEBUG_ARG("m = %lx", (long)m);
  85         DEBUG_ARG("m->m_len = %d", m->m_len);
  86
  87         /* Shouldn't happen, but...  e.g. foreign host closes connection */
  88         if (m->m_len <= 0) {
  89                 m_free(m);
  90                 return;
  91         }
  92
  93         /*
  94          * If there is urgent data, call sosendoob
  95          * if not all was sent, sowrite will take care of the rest
  96          * (The rest of this function is just an optimisation)
  97          */
  98         if (so->so_urgc) {
  99                 sbappendsb(&so->so_rcv, m);
 100                 m_free(m);
 101                 sosendoob(so);
 102                 return;
 103         }
 104
 105         /*
 106          * We only write if there's nothing in the buffer,
 107          * ottherwise it'll arrive out of order, and hence corrupt
 108          */
 109         if (!so->so_rcv.sb_cc)
 110            ret = write(so->s, m->m_data, m->m_len);
 111
 112         if (ret <= 0) {
 113                 /*
 114                  * Nothing was written
 115                  * It's possible that the socket has closed, but
 116                  * we don't need to check because if it has closed,
 117                  * it will be detected in the normal way by soread()
 118                  */
 119                 sbappendsb(&so->so_rcv, m);
 120         } else if (ret != m->m_len) {
 121                 /*
 122                  * Something was written, but not everything..
 123                  * sbappendsb the rest
 124                  */
 125                 m->m_len -= ret;
 126                 m->m_data += ret;
 127                 sbappendsb(&so->so_rcv, m);
 128         } /* else */
 129         /* Whatever happened, we free the mbuf */
 130         m_free(m);
 131 }
 132
 133 /*
 134  * Copy the data from m into sb
 135  * The caller is responsible to make sure there's enough room
 136  */
 137 void
 138 sbappendsb(sb, m)
 139          struct sbuf *sb;
 140          struct mbuf *m;
 141 {
 142         int len, n,  nn;
 143
 144         len = m->m_len;
 145
 146         if (sb->sb_wptr < sb->sb_rptr) {
 147                 n = sb->sb_rptr - sb->sb_wptr;
 148                 if (n > len) n = len;
 149                 memcpy(sb->sb_wptr, m->m_data, n);
 150         } else {
 151                 /* Do the right edge first */
 152                 n = sb->sb_data + sb->sb_datalen - sb->sb_wptr;
 153                 if (n > len) n = len;
 154                 memcpy(sb->sb_wptr, m->m_data, n);
 155                 len -= n;
 156                 if (len) {
 157                         /* Now the left edge */
 158                         nn = sb->sb_rptr - sb->sb_data;
 159                         if (nn > len) nn = len;
 160                         memcpy(sb->sb_data,m->m_data+n,nn);
 161                         n += nn;
 162                 }
 163         }
 164
 165         sb->sb_cc += n;
 166         sb->sb_wptr += n;
 167         if (sb->sb_wptr >= sb->sb_data + sb->sb_datalen)
 168                 sb->sb_wptr -= sb->sb_datalen;
 169 }
 170
 171 /*
 172  * Copy data from sbuf to a normal, straight buffer
 173  * Don't update the sbuf rptr, this will be
 174  * done in sbdrop when the data is acked
 175  */
 176 void
 177 sbcopy(sb, off, len, to)
 178         struct sbuf *sb;
 179         int off;
 180         int len;
 181         char *to;
 182 {
 183         char *from;
 184
 185         from = sb->sb_rptr + off;
 186         if (from >= sb->sb_data + sb->sb_datalen)
 187                 from -= sb->sb_datalen;
 188
 189         if (from < sb->sb_wptr) {
 190                 if (len > sb->sb_cc) len = sb->sb_cc;
 191                 memcpy(to,from,len);
 192         } else {
 193                 /* re-use off */
 194                 off = (sb->sb_data + sb->sb_datalen) - from;
 195                 if (off > len) off = len;
 196                 memcpy(to,from,off);
 197                 len -= off;
 198                 if (len)
 199                    memcpy(to+off,sb->sb_data,len);
 200         }
 201 }
 202