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authorfishsoupisgood <github@madingley.org>2019-04-29 01:17:54 +0100
committerfishsoupisgood <github@madingley.org>2019-05-27 03:43:43 +0100
commit3f2546b2ef55b661fd8dd69682b38992225e86f6 (patch)
tree65ca85f13617aee1dce474596800950f266a456c /slirp/sbuf.c
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Initial import of qemu-2.4.1HEADmaster
Diffstat (limited to 'slirp/sbuf.c')
-rw-r--r--slirp/sbuf.c187
1 files changed, 187 insertions, 0 deletions
diff --git a/slirp/sbuf.c b/slirp/sbuf.c
new file mode 100644
index 00000000..08ec2b4f
--- /dev/null
+++ b/slirp/sbuf.c
@@ -0,0 +1,187 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include <qemu/main-loop.h>
+
+static void sbappendsb(struct sbuf *sb, struct mbuf *m);
+
+void
+sbfree(struct sbuf *sb)
+{
+ free(sb->sb_data);
+}
+
+void
+sbdrop(struct sbuf *sb, int num)
+{
+ int limit = sb->sb_datalen / 2;
+
+ /*
+ * We can only drop how much we have
+ * This should never succeed
+ */
+ if(num > sb->sb_cc)
+ num = sb->sb_cc;
+ sb->sb_cc -= num;
+ sb->sb_rptr += num;
+ if(sb->sb_rptr >= sb->sb_data + sb->sb_datalen)
+ sb->sb_rptr -= sb->sb_datalen;
+
+ if (sb->sb_cc < limit && sb->sb_cc + num >= limit) {
+ qemu_notify_event();
+ }
+}
+
+void
+sbreserve(struct sbuf *sb, int size)
+{
+ if (sb->sb_data) {
+ /* Already alloced, realloc if necessary */
+ if (sb->sb_datalen != size) {
+ sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)realloc(sb->sb_data, size);
+ sb->sb_cc = 0;
+ if (sb->sb_wptr)
+ sb->sb_datalen = size;
+ else
+ sb->sb_datalen = 0;
+ }
+ } else {
+ sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)malloc(size);
+ sb->sb_cc = 0;
+ if (sb->sb_wptr)
+ sb->sb_datalen = size;
+ else
+ sb->sb_datalen = 0;
+ }
+}
+
+/*
+ * Try and write() to the socket, whatever doesn't get written
+ * append to the buffer... for a host with a fast net connection,
+ * this prevents an unnecessary copy of the data
+ * (the socket is non-blocking, so we won't hang)
+ */
+void
+sbappend(struct socket *so, struct mbuf *m)
+{
+ int ret = 0;
+
+ DEBUG_CALL("sbappend");
+ DEBUG_ARG("so = %lx", (long)so);
+ DEBUG_ARG("m = %lx", (long)m);
+ DEBUG_ARG("m->m_len = %d", m->m_len);
+
+ /* Shouldn't happen, but... e.g. foreign host closes connection */
+ if (m->m_len <= 0) {
+ m_free(m);
+ return;
+ }
+
+ /*
+ * If there is urgent data, call sosendoob
+ * if not all was sent, sowrite will take care of the rest
+ * (The rest of this function is just an optimisation)
+ */
+ if (so->so_urgc) {
+ sbappendsb(&so->so_rcv, m);
+ m_free(m);
+ sosendoob(so);
+ return;
+ }
+
+ /*
+ * We only write if there's nothing in the buffer,
+ * ottherwise it'll arrive out of order, and hence corrupt
+ */
+ if (!so->so_rcv.sb_cc)
+ ret = slirp_send(so, m->m_data, m->m_len, 0);
+
+ if (ret <= 0) {
+ /*
+ * Nothing was written
+ * It's possible that the socket has closed, but
+ * we don't need to check because if it has closed,
+ * it will be detected in the normal way by soread()
+ */
+ sbappendsb(&so->so_rcv, m);
+ } else if (ret != m->m_len) {
+ /*
+ * Something was written, but not everything..
+ * sbappendsb the rest
+ */
+ m->m_len -= ret;
+ m->m_data += ret;
+ sbappendsb(&so->so_rcv, m);
+ } /* else */
+ /* Whatever happened, we free the mbuf */
+ m_free(m);
+}
+
+/*
+ * Copy the data from m into sb
+ * The caller is responsible to make sure there's enough room
+ */
+static void
+sbappendsb(struct sbuf *sb, struct mbuf *m)
+{
+ int len, n, nn;
+
+ len = m->m_len;
+
+ if (sb->sb_wptr < sb->sb_rptr) {
+ n = sb->sb_rptr - sb->sb_wptr;
+ if (n > len) n = len;
+ memcpy(sb->sb_wptr, m->m_data, n);
+ } else {
+ /* Do the right edge first */
+ n = sb->sb_data + sb->sb_datalen - sb->sb_wptr;
+ if (n > len) n = len;
+ memcpy(sb->sb_wptr, m->m_data, n);
+ len -= n;
+ if (len) {
+ /* Now the left edge */
+ nn = sb->sb_rptr - sb->sb_data;
+ if (nn > len) nn = len;
+ memcpy(sb->sb_data,m->m_data+n,nn);
+ n += nn;
+ }
+ }
+
+ sb->sb_cc += n;
+ sb->sb_wptr += n;
+ if (sb->sb_wptr >= sb->sb_data + sb->sb_datalen)
+ sb->sb_wptr -= sb->sb_datalen;
+}
+
+/*
+ * Copy data from sbuf to a normal, straight buffer
+ * Don't update the sbuf rptr, this will be
+ * done in sbdrop when the data is acked
+ */
+void
+sbcopy(struct sbuf *sb, int off, int len, char *to)
+{
+ char *from;
+
+ from = sb->sb_rptr + off;
+ if (from >= sb->sb_data + sb->sb_datalen)
+ from -= sb->sb_datalen;
+
+ if (from < sb->sb_wptr) {
+ if (len > sb->sb_cc) len = sb->sb_cc;
+ memcpy(to,from,len);
+ } else {
+ /* re-use off */
+ off = (sb->sb_data + sb->sb_datalen) - from;
+ if (off > len) off = len;
+ memcpy(to,from,off);
+ len -= off;
+ if (len)
+ memcpy(to+off,sb->sb_data,len);
+ }
+}