src/slirp/bootp.c

/*
 * QEMU BOOTP/DHCP server
 * 
 * Copyright (c) 2004 Fabrice Bellard
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include <slirp.h>

/* XXX: only DHCP is supported */

#define NB_ADDR 16

#define START_ADDR 15

#define LEASE_TIME (24 * 3600)

typedef struct {
    uint8_t allocated;
    uint8_t macaddr[6];
} BOOTPClient;

BOOTPClient bootp_clients[NB_ADDR];

static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };

static BOOTPClient *get_new_addr(struct in_addr *paddr)
{
    BOOTPClient *bc;
    int i;

    for(i = 0; i < NB_ADDR; i++) {
        if (!bootp_clients[i].allocated)
            goto found;
    }
    return NULL;
 found:
    bc = &bootp_clients[i];
    bc->allocated = 1;
    paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR));
    return bc;
}

static BOOTPClient *find_addr(struct in_addr *paddr, const uint8_t *macaddr)
{
    BOOTPClient *bc;
    int i;

    for(i = 0; i < NB_ADDR; i++) {
        if (!memcmp(macaddr, bootp_clients[i].macaddr, 6))
            goto found;
    }
    return NULL;
 found:
    bc = &bootp_clients[i];
    bc->allocated = 1;
    paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR));
    return bc;
}

static void dhcp_decode(const uint8_t *buf, int size,
                        int *pmsg_type)
{
    const uint8_t *p, *p_end;
    int len, tag;

    *pmsg_type = 0;    

    p = buf;
    p_end = buf + size;
    if (size < 5)
        return;
    if (memcmp(p, rfc1533_cookie, 4) != 0)
        return;
    p += 4;
    while (p < p_end) {
        tag = p[0];
        if (tag == RFC1533_PAD) {
            p++; 
        } else if (tag == RFC1533_END) {
            break;
        } else {
            p++;
            if (p >= p_end)
                break;
            len = *p++;

            switch(tag) {
            case RFC2132_MSG_TYPE:
                if (len >= 1)
                    *pmsg_type = p[0];
                break;
            default:
                break;
            }
            p += len;
        }
    }
}

static void bootp_reply(struct bootp_t *bp)
{
    BOOTPClient *bc;
    struct mbuf *m;
    struct bootp_t *rbp;
    struct sockaddr_in saddr, daddr;
    struct in_addr dns_addr;
    int dhcp_msg_type, val;
    uint8_t *q;

    /* extract exact DHCP msg type */
    dhcp_decode(bp->bp_vend, DHCP_OPT_LEN, &dhcp_msg_type);
    
    if (dhcp_msg_type == 0)
        dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
        
    if (dhcp_msg_type != DHCPDISCOVER && 
        dhcp_msg_type != DHCPREQUEST)
        return;
    /* XXX: this is a hack to get the client mac address */
    memcpy(client_ethaddr, bp->bp_hwaddr, 6);
    
    if ((m = m_get()) == NULL)
        return;
    m->m_data += if_maxlinkhdr;
    rbp = (struct bootp_t *)m->m_data;
    m->m_data += sizeof(struct udpiphdr);
    memset(rbp, 0, sizeof(struct bootp_t));

    if (dhcp_msg_type == DHCPDISCOVER) {
    new_addr:
        bc = get_new_addr(&daddr.sin_addr);
        if (!bc)
            return;
        memcpy(bc->macaddr, client_ethaddr, 6);
    } else {
        bc = find_addr(&daddr.sin_addr, bp->bp_hwaddr);
        if (!bc) {
            /* if never assigned, behaves as if it was already
               assigned (windows fix because it remembers its address) */
            goto new_addr;
        }
    }

    saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_ALIAS);
    saddr.sin_port = htons(BOOTP_SERVER);

    daddr.sin_port = htons(BOOTP_CLIENT);

    rbp->bp_op = BOOTP_REPLY;
    rbp->bp_xid = bp->bp_xid;
    rbp->bp_htype = 1;
    rbp->bp_hlen = 6;
    memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);

    rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
    rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */

    q = rbp->bp_vend;
    memcpy(q, rfc1533_cookie, 4);
    q += 4;

    if (dhcp_msg_type == DHCPDISCOVER) {
        *q++ = RFC2132_MSG_TYPE;
        *q++ = 1;
        *q++ = DHCPOFFER;
    } else if (dhcp_msg_type == DHCPREQUEST) {
        *q++ = RFC2132_MSG_TYPE;
        *q++ = 1;
        *q++ = DHCPACK;
    }
        
    if (dhcp_msg_type == DHCPDISCOVER ||
        dhcp_msg_type == DHCPREQUEST) {
        *q++ = RFC2132_SRV_ID;
        *q++ = 4;
        memcpy(q, &saddr.sin_addr, 4);
        q += 4;

        *q++ = RFC1533_NETMASK;
        *q++ = 4;
        *q++ = 0xff;
        *q++ = 0xff;
        *q++ = 0xff;
        *q++ = 0x00;
        
        *q++ = RFC1533_GATEWAY;
        *q++ = 4;
        memcpy(q, &saddr.sin_addr, 4);
        q += 4;
        
        *q++ = RFC1533_DNS;
        *q++ = 4;
        dns_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_DNS);
        memcpy(q, &dns_addr, 4);
        q += 4;

        *q++ = RFC2132_LEASE_TIME;
        *q++ = 4;
        val = htonl(LEASE_TIME);
        memcpy(q, &val, 4);
        q += 4;

        if (*slirp_hostname) {
            val = strlen(slirp_hostname);
            *q++ = RFC1533_HOSTNAME;
            *q++ = val;
            memcpy(q, slirp_hostname, val);
            q += val;
        }
    }
    *q++ = RFC1533_END;
    
    m->m_len = sizeof(struct bootp_t) - 
        sizeof(struct ip) - sizeof(struct udphdr);
    udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
}

void bootp_input(struct mbuf *m)
{
    struct bootp_t *bp = mtod(m, struct bootp_t *);

    if (bp->bp_op == BOOTP_REQUEST) {
        bootp_reply(bp);
    }
}
Revision:	1.4
Committed:	2007-11-03T11:11:42Z (16 years, 7 months ago) by gbeauche
Content type:	text/plain
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.3:	+8 -0 lines
Log Message:	Update to slirp sources from QEMU 0.8.2: - set slirp client hostname - fix slirp redirection on systems without a useful host IP address - separate alias_addr (10.0.2.2) from our_addr (Ed Swierk) - fix 32+ KB packets handling (Ed Swierk) - fix UDP broadcast translation error - solaris port (Ben Taylor)
#	User	Rev	Content
1	gbeauche	1.1	/*
2			* QEMU BOOTP/DHCP server
3			*
4			* Copyright (c) 2004 Fabrice Bellard
5			*
6			* Permission is hereby granted, free of charge, to any person obtaining a copy
7			* of this software and associated documentation files (the "Software"), to deal
8			* in the Software without restriction, including without limitation the rights
9			* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10			* copies of the Software, and to permit persons to whom the Software is
11			* furnished to do so, subject to the following conditions:
12			*
13			* The above copyright notice and this permission notice shall be included in
14			* all copies or substantial portions of the Software.
15			*
16			* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17			* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18			* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19			* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20			* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21			* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22			* THE SOFTWARE.
23			*/
24			#include <slirp.h>
25
26			/* XXX: only DHCP is supported */
27
28			#define NB_ADDR 16
29
30			#define START_ADDR 15
31
32			#define LEASE_TIME (24 * 3600)
33
34			typedef struct {
35			uint8_t allocated;
36			uint8_t macaddr[6];
37			} BOOTPClient;
38
39			BOOTPClient bootp_clients[NB_ADDR];
40
41			static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
42
43			static BOOTPClient get_new_addr(struct in_addr paddr)
44			{
45			BOOTPClient *bc;
46			int i;
47
48			for(i = 0; i < NB_ADDR; i++) {
49			if (!bootp_clients[i].allocated)
50			goto found;
51			}
52			return NULL;
53			found:
54			bc = &bootp_clients[i];
55			bc->allocated = 1;
56			paddr->s_addr = htonl(ntohl(special_addr.s_addr) \| (i + START_ADDR));
57			return bc;
58			}
59
60			static BOOTPClient find_addr(struct in_addr paddr, const uint8_t *macaddr)
61			{
62			BOOTPClient *bc;
63			int i;
64
65			for(i = 0; i < NB_ADDR; i++) {
66			if (!memcmp(macaddr, bootp_clients[i].macaddr, 6))
67			goto found;
68			}
69			return NULL;
70			found:
71			bc = &bootp_clients[i];
72			bc->allocated = 1;
73			paddr->s_addr = htonl(ntohl(special_addr.s_addr) \| (i + START_ADDR));
74			return bc;
75			}
76
77			static void dhcp_decode(const uint8_t *buf, int size,
78			int *pmsg_type)
79			{
80			const uint8_t p, p_end;
81			int len, tag;
82
83			*pmsg_type = 0;
84
85			p = buf;
86			p_end = buf + size;
87			if (size < 5)
88			return;
89			if (memcmp(p, rfc1533_cookie, 4) != 0)
90			return;
91			p += 4;
92			while (p < p_end) {
93			tag = p[0];
94			if (tag == RFC1533_PAD) {
95			p++;
96			} else if (tag == RFC1533_END) {
97			break;
98			} else {
99			p++;
100			if (p >= p_end)
101			break;
102			len = *p++;
103
104			switch(tag) {
105			case RFC2132_MSG_TYPE:
106			if (len >= 1)
107			*pmsg_type = p[0];
108			break;
109			default:
110			break;
111			}
112			p += len;
113			}
114			}
115			}
116
117			static void bootp_reply(struct bootp_t *bp)
118			{
119			BOOTPClient *bc;
120			struct mbuf *m;
121			struct bootp_t *rbp;
122			struct sockaddr_in saddr, daddr;
123			struct in_addr dns_addr;
124			int dhcp_msg_type, val;
125			uint8_t *q;
126
127			/* extract exact DHCP msg type */
128			dhcp_decode(bp->bp_vend, DHCP_OPT_LEN, &dhcp_msg_type);
129
130			if (dhcp_msg_type == 0)
131			dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
132
133			if (dhcp_msg_type != DHCPDISCOVER &&
134			dhcp_msg_type != DHCPREQUEST)
135			return;
136			/* XXX: this is a hack to get the client mac address */
137			memcpy(client_ethaddr, bp->bp_hwaddr, 6);
138
139			if ((m = m_get()) == NULL)
140			return;
141			m->m_data += if_maxlinkhdr;
142			rbp = (struct bootp_t *)m->m_data;
143			m->m_data += sizeof(struct udpiphdr);
144			memset(rbp, 0, sizeof(struct bootp_t));
145
146			if (dhcp_msg_type == DHCPDISCOVER) {
147			new_addr:
148			bc = get_new_addr(&daddr.sin_addr);
149	gbeauche	1.3	if (!bc)
150	gbeauche	1.1	return;
151			memcpy(bc->macaddr, client_ethaddr, 6);
152			} else {
153			bc = find_addr(&daddr.sin_addr, bp->bp_hwaddr);
154			if (!bc) {
155			/* if never assigned, behaves as if it was already
156			assigned (windows fix because it remembers its address) */
157			goto new_addr;
158			}
159			}
160
161			saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) \| CTL_ALIAS);
162			saddr.sin_port = htons(BOOTP_SERVER);
163
164			daddr.sin_port = htons(BOOTP_CLIENT);
165
166			rbp->bp_op = BOOTP_REPLY;
167			rbp->bp_xid = bp->bp_xid;
168			rbp->bp_htype = 1;
169			rbp->bp_hlen = 6;
170			memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
171
172			rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
173			rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */
174
175			q = rbp->bp_vend;
176			memcpy(q, rfc1533_cookie, 4);
177			q += 4;
178
179			if (dhcp_msg_type == DHCPDISCOVER) {
180			*q++ = RFC2132_MSG_TYPE;
181			*q++ = 1;
182			*q++ = DHCPOFFER;
183			} else if (dhcp_msg_type == DHCPREQUEST) {
184			*q++ = RFC2132_MSG_TYPE;
185			*q++ = 1;
186			*q++ = DHCPACK;
187			}
188
189			if (dhcp_msg_type == DHCPDISCOVER \|\|
190			dhcp_msg_type == DHCPREQUEST) {
191			*q++ = RFC2132_SRV_ID;
192			*q++ = 4;
193			memcpy(q, &saddr.sin_addr, 4);
194			q += 4;
195
196			*q++ = RFC1533_NETMASK;
197			*q++ = 4;
198			*q++ = 0xff;
199			*q++ = 0xff;
200			*q++ = 0xff;
201			*q++ = 0x00;
202
203			*q++ = RFC1533_GATEWAY;
204			*q++ = 4;
205			memcpy(q, &saddr.sin_addr, 4);
206			q += 4;
207
208			*q++ = RFC1533_DNS;
209			*q++ = 4;
210			dns_addr.s_addr = htonl(ntohl(special_addr.s_addr) \| CTL_DNS);
211			memcpy(q, &dns_addr, 4);
212			q += 4;
213
214			*q++ = RFC2132_LEASE_TIME;
215			*q++ = 4;
216			val = htonl(LEASE_TIME);
217			memcpy(q, &val, 4);
218			q += 4;
219	gbeauche	1.4
220			if (*slirp_hostname) {
221			val = strlen(slirp_hostname);
222			*q++ = RFC1533_HOSTNAME;
223			*q++ = val;
224			memcpy(q, slirp_hostname, val);
225			q += val;
226			}
227	gbeauche	1.1	}
228			*q++ = RFC1533_END;
229
230			m->m_len = sizeof(struct bootp_t) -
231			sizeof(struct ip) - sizeof(struct udphdr);
232			udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
233			}
234
235			void bootp_input(struct mbuf *m)
236			{
237	gbeauche	1.2	struct bootp_t bp = mtod(m, struct bootp_t );
238	gbeauche	1.1
239			if (bp->bp_op == BOOTP_REQUEST) {
240			bootp_reply(bp);
241			}
242			}