From f0cbd3ec9f4a3de1a9ef94deda09704543889f44 Mon Sep 17 00:00:00 2001
From: bellard <bellard@c046a42c-6fe2-441c-8c8c-71466251a162>
Date: Thu, 22 Apr 2004 00:10:48 +0000
Subject: initial user mode network support

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@733 c046a42c-6fe2-441c-8c8c-71466251a162
---
 slirp/sbuf.c | 201 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 201 insertions(+)
 create mode 100644 slirp/sbuf.c

(limited to 'slirp/sbuf.c')

diff --git a/slirp/sbuf.c b/slirp/sbuf.c
new file mode 100644
index 0000000000..04fb97ddc8
--- /dev/null
+++ b/slirp/sbuf.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+
+/* Done as a macro in socket.h */
+/* int
+ * sbspace(struct sockbuff *sb) 
+ * {
+ *	return SB_DATALEN - sb->sb_cc;
+ * }
+ */
+
+void
+sbfree(sb)
+	struct sbuf *sb;
+{
+	free(sb->sb_data);
+}
+
+void
+sbdrop(sb, num)
+	struct sbuf *sb;
+	int num; 
+{
+	/* 
+	 * 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;
+   
+}
+
+void
+sbreserve(sb, size)
+	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(so, m)
+	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 = write(so->s, m->m_data, m->m_len);
+	
+	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
+ */
+void
+sbappendsb(sb, m)
+	 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(sb, off, len, to)
+	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);
+	}
+}
+		
-- 
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