networking/udhcp/script.c

/* vi: set sw=4 ts=4: */
/* script.c
 *
 * Functions to call the DHCP client notification scripts
 *
 * Russ Dill <Russ.Dill@asu.edu> July 2001
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "common.h"
#include "dhcpc.h"
#include "options.h"


/* get a rough idea of how long an option will be (rounding up...) */
static const uint8_t len_of_option_as_string[] = {
	[OPTION_IP] =		sizeof("255.255.255.255 "),
	[OPTION_IP_PAIR] =	sizeof("255.255.255.255 ") * 2,
	[OPTION_STATIC_ROUTES]= sizeof("255.255.255.255/32 255.255.255.255 "),
	[OPTION_STRING] =	1,
#if ENABLE_FEATURE_UDHCP_RFC3397
	[OPTION_STR1035] =	1,
#endif
	[OPTION_BOOLEAN] =	sizeof("yes "),
	[OPTION_U8] =		sizeof("255 "),
	[OPTION_U16] =		sizeof("65535 "),
	[OPTION_S16] =		sizeof("-32768 "),
	[OPTION_U32] =		sizeof("4294967295 "),
	[OPTION_S32] =		sizeof("-2147483684 "),
};


/* note: ip is a pointer to an IP in network order, possibly misaliged */
static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
{
	return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
}


/* really simple implementation, just count the bits */
static int mton(uint32_t mask)
{
	int i = 0;
	mask = ntohl(mask); /* 111110000-like bit pattern */
	while (mask) {
		i++;
		mask <<= 1;
	}
	return i;
}


/* Create "opt_name=opt_value" string */
static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_option *type_p, const char *opt_name)
{
	unsigned upper_length;
	int len, type, optlen;
	uint16_t val_u16;
	int16_t val_s16;
	uint32_t val_u32;
	int32_t val_s32;
	char *dest, *ret;

	/* option points to OPT_DATA, need to go back and get OPT_LEN */
	len = option[OPT_LEN - OPT_DATA];
	type = type_p->flags & TYPE_MASK;
	optlen = dhcp_option_lengths[type];
	upper_length = len_of_option_as_string[type] * (len / optlen);

	dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
	dest += sprintf(ret, "%s=", opt_name);

	while (len >= optlen) {
		switch (type) {
		case OPTION_IP_PAIR:
			dest += sprint_nip(dest, "", option);
			*dest++ = '/';
			option += 4;
			optlen = 4;
		case OPTION_IP:	/* Works regardless of host byte order. */
			dest += sprint_nip(dest, "", option);
			break;
		case OPTION_BOOLEAN:
			dest += sprintf(dest, *option ? "yes" : "no");
			break;
		case OPTION_U8:
			dest += sprintf(dest, "%u", *option);
			break;
		case OPTION_U16:
			move_from_unaligned16(val_u16, option);
			dest += sprintf(dest, "%u", ntohs(val_u16));
			break;
		case OPTION_S16:
			move_from_unaligned16(val_s16, option);
			dest += sprintf(dest, "%d", ntohs(val_s16));
			break;
		case OPTION_U32:
			move_from_unaligned32(val_u32, option);
			dest += sprintf(dest, "%lu", (unsigned long) ntohl(val_u32));
			break;
		case OPTION_S32:
			move_from_unaligned32(val_s32, option);
			dest += sprintf(dest, "%ld", (long) ntohl(val_s32));
			break;
		case OPTION_STRING:
			memcpy(dest, option, len);
			dest[len] = '\0';
			return ret;	 /* Short circuit this case */
		case OPTION_STATIC_ROUTES: {
			/* Option binary format:
			 * mask [one byte, 0..32]
			 * ip [big endian, 0..4 bytes depending on mask]
			 * router [big endian, 4 bytes]
			 * may be repeated
			 *
			 * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
			 */
			const char *pfx = "";

			while (len >= 1 + 4) { /* mask + 0-byte ip + router */
				uint32_t nip;
				uint8_t *p;
				unsigned mask;
				int bytes;

				mask = *option++;
				if (mask > 32)
					break;
				len--;

				nip = 0;
				p = (void*) &nip;
				bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
				while (--bytes >= 0) {
					*p++ = *option++;
					len--;
				}
				if (len < 4)
					break;

				/* print ip/mask */
				dest += sprint_nip(dest, pfx, (void*) &nip);
				pfx = " ";
				dest += sprintf(dest, "/%u ", mask);
				/* print router */
				dest += sprint_nip(dest, "", option);
				option += 4;
				len -= 4;
			}

			return ret;
		}
#if ENABLE_FEATURE_UDHCP_RFC3397
		case OPTION_STR1035:
			/* unpack option into dest; use ret for prefix (i.e., "optname=") */
			dest = dname_dec(option, len, ret);
			if (dest) {
				free(ret);
				return dest;
			}
			/* error. return "optname=" string */
			return ret;
#endif
		}
		option += optlen;
		len -= optlen;
		if (len <= 0)
			break;
		*dest++ = ' ';
		*dest = '\0';
	}
	return ret;
}


/* put all the parameters into an environment */
static char **fill_envp(struct dhcp_packet *packet)
{
	int num_options = 0;
	int i;
	char **envp, **curr;
	const char *opt_name;
	uint8_t *temp;
	uint8_t over = 0;

	if (packet) {
		for (i = 0; dhcp_options[i].code; i++) {
			if (get_option(packet, dhcp_options[i].code)) {
				num_options++;
				if (dhcp_options[i].code == DHCP_SUBNET)
					num_options++; /* for mton */
			}
		}
		if (packet->siaddr_nip)
			num_options++;
		temp = get_option(packet, DHCP_OPTION_OVERLOAD);
		if (temp)
			over = *temp;
		if (!(over & FILE_FIELD) && packet->file[0])
			num_options++;
		if (!(over & SNAME_FIELD) && packet->sname[0])
			num_options++;
	}

	curr = envp = xzalloc(sizeof(char *) * (num_options + 3));
	*curr = xasprintf("interface=%s", client_config.interface);
	putenv(*curr++);

	if (packet == NULL)
		return envp;

	*curr = xmalloc(sizeof("ip=255.255.255.255"));
	sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
	putenv(*curr++);

	opt_name = dhcp_option_strings;
	i = 0;
	while (*opt_name) {
		temp = get_option(packet, dhcp_options[i].code);
		if (!temp)
			goto next;
		*curr = xmalloc_optname_optval(temp, &dhcp_options[i], opt_name);
		putenv(*curr++);

		/* Fill in a subnet bits option for things like /24 */
		if (dhcp_options[i].code == DHCP_SUBNET) {
			uint32_t subnet;
			move_from_unaligned32(subnet, temp);
			*curr = xasprintf("mask=%d", mton(subnet));
			putenv(*curr++);
		}
 next:
		opt_name += strlen(opt_name) + 1;
		i++;
	}
	if (packet->siaddr_nip) {
		*curr = xmalloc(sizeof("siaddr=255.255.255.255"));
		sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
		putenv(*curr++);
	}
	if (!(over & FILE_FIELD) && packet->file[0]) {
		/* watch out for invalid packets */
		packet->file[sizeof(packet->file) - 1] = '\0';
		*curr = xasprintf("boot_file=%s", packet->file);
		putenv(*curr++);
	}
	if (!(over & SNAME_FIELD) && packet->sname[0]) {
		/* watch out for invalid packets */
		packet->sname[sizeof(packet->sname) - 1] = '\0';
		*curr = xasprintf("sname=%s", packet->sname);
		putenv(*curr++);
	}
	return envp;
}


/* Call a script with a par file and env vars */
void FAST_FUNC udhcp_run_script(struct dhcp_packet *packet, const char *name)
{
	char **envp, **curr;
	char *argv[3];

	if (client_config.script == NULL)
		return;

	envp = fill_envp(packet);

	/* call script */
	log1("Executing %s %s", client_config.script, name);
	argv[0] = (char*) client_config.script;
	argv[1] = (char*) name;
	argv[2] = NULL;
	wait4pid(spawn(argv));

	for (curr = envp; *curr; curr++) {
		log2(" %s", *curr);
		bb_unsetenv(*curr);
		free(*curr);
	}
	free(envp);
}
1	/* vi: set sw=4 ts=4: */
2	/* script.c
3	*
4	* Functions to call the DHCP client notification scripts
5	*
6	* Russ Dill <Russ.Dill@asu.edu> July 2001
7	*
8	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
9	*/
10
11	#include "common.h"
12	#include "dhcpc.h"
13	#include "options.h"
14
15
16	/* get a rough idea of how long an option will be (rounding up...) */
17	static const uint8_t len_of_option_as_string[] = {
18	[OPTION_IP] = sizeof("255.255.255.255 "),
19	[OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2,
20	[OPTION_STATIC_ROUTES]= sizeof("255.255.255.255/32 255.255.255.255 "),
21	[OPTION_STRING] = 1,
22	#if ENABLE_FEATURE_UDHCP_RFC3397
23	[OPTION_STR1035] = 1,
24	#endif
25	[OPTION_BOOLEAN] = sizeof("yes "),
26	[OPTION_U8] = sizeof("255 "),
27	[OPTION_U16] = sizeof("65535 "),
28	[OPTION_S16] = sizeof("-32768 "),
29	[OPTION_U32] = sizeof("4294967295 "),
30	[OPTION_S32] = sizeof("-2147483684 "),
31	};
32
33
34	/* note: ip is a pointer to an IP in network order, possibly misaliged */
35	static int sprint_nip(char dest, const char pre, const uint8_t *ip)
36	{
37	return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
38	}
39
40
41	/* really simple implementation, just count the bits */
42	static int mton(uint32_t mask)
43	{
44	int i = 0;
45	mask = ntohl(mask); /* 111110000-like bit pattern */
46	while (mask) {
47	i++;
48	mask <<= 1;
49	}
50	return i;
51	}
52
53
54	/* Create "opt_name=opt_value" string */
55	static NOINLINE char xmalloc_optname_optval(uint8_t option, const struct dhcp_option type_p, const char opt_name)
56	{
57	unsigned upper_length;
58	int len, type, optlen;
59	uint16_t val_u16;
60	int16_t val_s16;
61	uint32_t val_u32;
62	int32_t val_s32;
63	char dest, ret;
64
65	/* option points to OPT_DATA, need to go back and get OPT_LEN */
66	len = option[OPT_LEN - OPT_DATA];
67	type = type_p->flags & TYPE_MASK;
68	optlen = dhcp_option_lengths[type];
69	upper_length = len_of_option_as_string[type] * (len / optlen);
70
71	dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
72	dest += sprintf(ret, "%s=", opt_name);
73
74	while (len >= optlen) {
75	switch (type) {
76	case OPTION_IP_PAIR:
77	dest += sprint_nip(dest, "", option);
78	*dest++ = '/';
79	option += 4;
80	optlen = 4;
81	case OPTION_IP: /* Works regardless of host byte order. */
82	dest += sprint_nip(dest, "", option);
83	break;
84	case OPTION_BOOLEAN:
85	dest += sprintf(dest, *option ? "yes" : "no");
86	break;
87	case OPTION_U8:
88	dest += sprintf(dest, "%u", *option);
89	break;
90	case OPTION_U16:
91	move_from_unaligned16(val_u16, option);
92	dest += sprintf(dest, "%u", ntohs(val_u16));
93	break;
94	case OPTION_S16:
95	move_from_unaligned16(val_s16, option);
96	dest += sprintf(dest, "%d", ntohs(val_s16));
97	break;
98	case OPTION_U32:
99	move_from_unaligned32(val_u32, option);
100	dest += sprintf(dest, "%lu", (unsigned long) ntohl(val_u32));
101	break;
102	case OPTION_S32:
103	move_from_unaligned32(val_s32, option);
104	dest += sprintf(dest, "%ld", (long) ntohl(val_s32));
105	break;
106	case OPTION_STRING:
107	memcpy(dest, option, len);
108	dest[len] = '\0';
109	return ret; /* Short circuit this case */
110	case OPTION_STATIC_ROUTES: {
111	/* Option binary format:
112	* mask [one byte, 0..32]
113	* ip [big endian, 0..4 bytes depending on mask]
114	* router [big endian, 4 bytes]
115	* may be repeated
116	*
117	* We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
118	*/
119	const char *pfx = "";
120
121	while (len >= 1 + 4) { /* mask + 0-byte ip + router */
122	uint32_t nip;
123	uint8_t *p;
124	unsigned mask;
125	int bytes;
126
127	mask = *option++;
128	if (mask > 32)
129	break;
130	len--;
131
132	nip = 0;
133	p = (void*) &nip;
134	bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
135	while (--bytes >= 0) {
136	p++ = option++;
137	len--;
138	}
139	if (len < 4)
140	break;
141
142	/* print ip/mask */
143	dest += sprint_nip(dest, pfx, (void*) &nip);
144	pfx = " ";
145	dest += sprintf(dest, "/%u ", mask);
146	/* print router */
147	dest += sprint_nip(dest, "", option);
148	option += 4;
149	len -= 4;
150	}
151
152	return ret;
153	}
154	#if ENABLE_FEATURE_UDHCP_RFC3397
155	case OPTION_STR1035:
156	/* unpack option into dest; use ret for prefix (i.e., "optname=") */
157	dest = dname_dec(option, len, ret);
158	if (dest) {
159	free(ret);
160	return dest;
161	}
162	/* error. return "optname=" string */
163	return ret;
164	#endif
165	}
166	option += optlen;
167	len -= optlen;
168	if (len <= 0)
169	break;
170	*dest++ = ' ';
171	*dest = '\0';
172	}
173	return ret;
174	}
175
176
177	/* put all the parameters into an environment */
178	static char *fill_envp(struct dhcp_packet packet)
179	{
180	int num_options = 0;
181	int i;
182	char envp, curr;
183	const char *opt_name;
184	uint8_t *temp;
185	uint8_t over = 0;
186
187	if (packet) {
188	for (i = 0; dhcp_options[i].code; i++) {
189	if (get_option(packet, dhcp_options[i].code)) {
190	num_options++;
191	if (dhcp_options[i].code == DHCP_SUBNET)
192	num_options++; /* for mton */
193	}
194	}
195	if (packet->siaddr_nip)
196	num_options++;
197	temp = get_option(packet, DHCP_OPTION_OVERLOAD);
198	if (temp)
199	over = *temp;
200	if (!(over & FILE_FIELD) && packet->file[0])
201	num_options++;
202	if (!(over & SNAME_FIELD) && packet->sname[0])
203	num_options++;
204	}
205
206	curr = envp = xzalloc(sizeof(char ) (num_options + 3));
207	*curr = xasprintf("interface=%s", client_config.interface);
208	putenv(*curr++);
209
210	if (packet == NULL)
211	return envp;
212
213	*curr = xmalloc(sizeof("ip=255.255.255.255"));
214	sprint_nip(curr, "ip=", (uint8_t ) &packet->yiaddr);
215	putenv(*curr++);
216
217	opt_name = dhcp_option_strings;
218	i = 0;
219	while (*opt_name) {
220	temp = get_option(packet, dhcp_options[i].code);
221	if (!temp)
222	goto next;
223	*curr = xmalloc_optname_optval(temp, &dhcp_options[i], opt_name);
224	putenv(*curr++);
225
226	/* Fill in a subnet bits option for things like /24 */
227	if (dhcp_options[i].code == DHCP_SUBNET) {
228	uint32_t subnet;
229	move_from_unaligned32(subnet, temp);
230	*curr = xasprintf("mask=%d", mton(subnet));
231	putenv(*curr++);
232	}
233	next:
234	opt_name += strlen(opt_name) + 1;
235	i++;
236	}
237	if (packet->siaddr_nip) {
238	*curr = xmalloc(sizeof("siaddr=255.255.255.255"));
239	sprint_nip(curr, "siaddr=", (uint8_t ) &packet->siaddr_nip);
240	putenv(*curr++);
241	}
242	if (!(over & FILE_FIELD) && packet->file[0]) {
243	/* watch out for invalid packets */
244	packet->file[sizeof(packet->file) - 1] = '\0';
245	*curr = xasprintf("boot_file=%s", packet->file);
246	putenv(*curr++);
247	}
248	if (!(over & SNAME_FIELD) && packet->sname[0]) {
249	/* watch out for invalid packets */
250	packet->sname[sizeof(packet->sname) - 1] = '\0';
251	*curr = xasprintf("sname=%s", packet->sname);
252	putenv(*curr++);
253	}
254	return envp;
255	}
256
257
258	/* Call a script with a par file and env vars */
259	void FAST_FUNC udhcp_run_script(struct dhcp_packet packet, const char name)
260	{
261	char envp, curr;
262	char *argv[3];
263
264	if (client_config.script == NULL)
265	return;
266
267	envp = fill_envp(packet);
268
269	/* call script */
270	log1("Executing %s %s", client_config.script, name);
271	argv[0] = (char*) client_config.script;
272	argv[1] = (char*) name;
273	argv[2] = NULL;
274	wait4pid(spawn(argv));
275
276	for (curr = envp; *curr; curr++) {
277	log2(" %s", *curr);
278	bb_unsetenv(*curr);
279	free(*curr);
280	}
281	free(envp);
282	}