src/slirp/sbuf.c

/*
 * 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 = send(so->s, 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
 */
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);
        }
}
                
Revision:	1.1
Committed:	2005-05-13T09:00:59Z (19 years, 6 months ago) by gbeauche
Content type:	text/plain
Branch:	MAIN
CVS Tags:	nigel-build-19, nigel-build-17
Log Message:	slirp user mode network emulation code from qemu
#	User	Rev	Content
1	gbeauche	1.1	/*
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 <slirp.h>
9
10			/* Done as a macro in socket.h */
11			/* int
12			* sbspace(struct sockbuff *sb)
13			* {
14			* return SB_DATALEN - sb->sb_cc;
15			* }
16			*/
17
18			void
19			sbfree(sb)
20			struct sbuf *sb;
21			{
22			free(sb->sb_data);
23			}
24
25			void
26			sbdrop(sb, num)
27			struct sbuf *sb;
28			int num;
29			{
30			/*
31			* We can only drop how much we have
32			* This should never succeed
33			*/
34			if(num > sb->sb_cc)
35			num = sb->sb_cc;
36			sb->sb_cc -= num;
37			sb->sb_rptr += num;
38			if(sb->sb_rptr >= sb->sb_data + sb->sb_datalen)
39			sb->sb_rptr -= sb->sb_datalen;
40
41			}
42
43			void
44			sbreserve(sb, size)
45			struct sbuf *sb;
46			int size;
47			{
48			if (sb->sb_data) {
49			/* Already alloced, realloc if necessary */
50			if (sb->sb_datalen != size) {
51			sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)realloc(sb->sb_data, size);
52			sb->sb_cc = 0;
53			if (sb->sb_wptr)
54			sb->sb_datalen = size;
55			else
56			sb->sb_datalen = 0;
57			}
58			} else {
59			sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)malloc(size);
60			sb->sb_cc = 0;
61			if (sb->sb_wptr)
62			sb->sb_datalen = size;
63			else
64			sb->sb_datalen = 0;
65			}
66			}
67
68			/*
69			* Try and write() to the socket, whatever doesn't get written
70			* append to the buffer... for a host with a fast net connection,
71			* this prevents an unnecessary copy of the data
72			* (the socket is non-blocking, so we won't hang)
73			*/
74			void
75			sbappend(so, m)
76			struct socket *so;
77			struct mbuf *m;
78			{
79			int ret = 0;
80
81			DEBUG_CALL("sbappend");
82			DEBUG_ARG("so = %lx", (long)so);
83			DEBUG_ARG("m = %lx", (long)m);
84			DEBUG_ARG("m->m_len = %d", m->m_len);
85
86			/* Shouldn't happen, but... e.g. foreign host closes connection */
87			if (m->m_len <= 0) {
88			m_free(m);
89			return;
90			}
91
92			/*
93			* If there is urgent data, call sosendoob
94			* if not all was sent, sowrite will take care of the rest
95			* (The rest of this function is just an optimisation)
96			*/
97			if (so->so_urgc) {
98			sbappendsb(&so->so_rcv, m);
99			m_free(m);
100			sosendoob(so);
101			return;
102			}
103
104			/*
105			* We only write if there's nothing in the buffer,
106			* ottherwise it'll arrive out of order, and hence corrupt
107			*/
108			if (!so->so_rcv.sb_cc)
109			ret = send(so->s, m->m_data, m->m_len, 0);
110
111			if (ret <= 0) {
112			/*
113			* Nothing was written
114			* It's possible that the socket has closed, but
115			* we don't need to check because if it has closed,
116			* it will be detected in the normal way by soread()
117			*/
118			sbappendsb(&so->so_rcv, m);
119			} else if (ret != m->m_len) {
120			/*
121			* Something was written, but not everything..
122			* sbappendsb the rest
123			*/
124			m->m_len -= ret;
125			m->m_data += ret;
126			sbappendsb(&so->so_rcv, m);
127			} /* else */
128			/* Whatever happened, we free the mbuf */
129			m_free(m);
130			}
131
132			/*
133			* Copy the data from m into sb
134			* The caller is responsible to make sure there's enough room
135			*/
136			void
137			sbappendsb(sb, m)
138			struct sbuf *sb;
139			struct mbuf *m;
140			{
141			int len, n, nn;
142
143			len = m->m_len;
144
145			if (sb->sb_wptr < sb->sb_rptr) {
146			n = sb->sb_rptr - sb->sb_wptr;
147			if (n > len) n = len;
148			memcpy(sb->sb_wptr, m->m_data, n);
149			} else {
150			/* Do the right edge first */
151			n = sb->sb_data + sb->sb_datalen - sb->sb_wptr;
152			if (n > len) n = len;
153			memcpy(sb->sb_wptr, m->m_data, n);
154			len -= n;
155			if (len) {
156			/* Now the left edge */
157			nn = sb->sb_rptr - sb->sb_data;
158			if (nn > len) nn = len;
159			memcpy(sb->sb_data,m->m_data+n,nn);
160			n += nn;
161			}
162			}
163
164			sb->sb_cc += n;
165			sb->sb_wptr += n;
166			if (sb->sb_wptr >= sb->sb_data + sb->sb_datalen)
167			sb->sb_wptr -= sb->sb_datalen;
168			}
169
170			/*
171			* Copy data from sbuf to a normal, straight buffer
172			* Don't update the sbuf rptr, this will be
173			* done in sbdrop when the data is acked
174			*/
175			void
176			sbcopy(sb, off, len, to)
177			struct sbuf *sb;
178			int off;
179			int len;
180			char *to;
181			{
182			char *from;
183
184			from = sb->sb_rptr + off;
185			if (from >= sb->sb_data + sb->sb_datalen)
186			from -= sb->sb_datalen;
187
188			if (from < sb->sb_wptr) {
189			if (len > sb->sb_cc) len = sb->sb_cc;
190			memcpy(to,from,len);
191			} else {
192			/* re-use off */
193			off = (sb->sb_data + sb->sb_datalen) - from;
194			if (off > len) off = len;
195			memcpy(to,from,off);
196			len -= off;
197			if (len)
198			memcpy(to+off,sb->sb_data,len);
199			}
200			}
201