1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
24  */
25 
26 #include <unistd.h>
27 #include <netinet/in.h>
28 #include <libinetutil.h>
29 #include <inet/ip.h>
30 #include <strings.h>
31 #include <stddef.h>
32 #include <errno.h>
33 #include <libsocket_priv.h>
34 
35 /*
36  * Internet utility functions.
37  */
38 
39 /*
40  * Given a host-order address, calculate client's default net mask.
41  * Consult netmasks database to see if net is further subnetted.
42  * We'll only snag the first netmask that matches our criteria.
43  * We return the resultant netmask in host order.
44  */
45 void
get_netmask4(const struct in_addr * n_addrp,struct in_addr * s_addrp)46 get_netmask4(const struct in_addr *n_addrp, struct in_addr *s_addrp)
47 {
48 	struct in_addr	hp, tp;
49 
50 	/*
51 	 * First check if VLSM is in use.
52 	 */
53 	hp.s_addr = htonl(n_addrp->s_addr);
54 	if (getnetmaskbyaddr(hp, &tp) == 0) {
55 		s_addrp->s_addr = ntohl(tp.s_addr);
56 		return;
57 	}
58 
59 	/*
60 	 * Fall back on standard classed networks.
61 	 */
62 	if (IN_CLASSA(n_addrp->s_addr))
63 		s_addrp->s_addr = IN_CLASSA_NET;
64 	else if (IN_CLASSB(n_addrp->s_addr))
65 		s_addrp->s_addr = IN_CLASSB_NET;
66 	else if (IN_CLASSC(n_addrp->s_addr))
67 		s_addrp->s_addr = IN_CLASSC_NET;
68 	else
69 		s_addrp->s_addr = IN_CLASSE_NET;
70 }
71 
72 /*
73  * Checks if the IP addresses `ssp1' and `ssp2' are equal.
74  */
75 boolean_t
sockaddrcmp(const struct sockaddr_storage * ssp1,const struct sockaddr_storage * ssp2)76 sockaddrcmp(const struct sockaddr_storage *ssp1,
77     const struct sockaddr_storage *ssp2)
78 {
79 	struct in_addr addr1, addr2;
80 	const struct in6_addr *addr6p1, *addr6p2;
81 
82 	if (ssp1->ss_family != ssp2->ss_family)
83 		return (B_FALSE);
84 
85 	if (ssp1 == ssp2)
86 		return (B_TRUE);
87 
88 	switch (ssp1->ss_family) {
89 	case AF_INET:
90 		addr1 = ((const struct sockaddr_in *)ssp1)->sin_addr;
91 		addr2 = ((const struct sockaddr_in *)ssp2)->sin_addr;
92 		return (addr1.s_addr == addr2.s_addr);
93 	case AF_INET6:
94 		addr6p1 = &((const struct sockaddr_in6 *)ssp1)->sin6_addr;
95 		addr6p2 = &((const struct sockaddr_in6 *)ssp2)->sin6_addr;
96 		return (IN6_ARE_ADDR_EQUAL(addr6p1, addr6p2));
97 	}
98 	return (B_FALSE);
99 }
100 
101 /*
102  * Stores the netmask in `mask' for the given prefixlen `plen' and also sets
103  * `sa_family' in `mask'. Because this function does not require aligned
104  * access to the data inside of the sockaddr_in/6 structures, the code can
105  * use offsetof() to find the right place in the incoming structure. Why is
106  * using that beneficial? Less issues with lint. When using a direct cast
107  * of the struct sockaddr_storage structure to sockaddr_in6, a lint warning
108  * is generated because the former is composed of 16bit & 8bit elements whilst
109  * sockaddr_in6 has a 32bit alignment requirement.
110  */
111 int
plen2mask(uint_t prefixlen,sa_family_t af,struct sockaddr * mask)112 plen2mask(uint_t prefixlen, sa_family_t af, struct sockaddr *mask)
113 {
114 	uint8_t	*addr;
115 
116 	if (af == AF_INET) {
117 		if (prefixlen > IP_ABITS)
118 			return (EINVAL);
119 		bzero(mask, sizeof (struct sockaddr_in));
120 		addr = (uint8_t *)mask;
121 		addr += offsetof(struct sockaddr_in, sin_addr);
122 	} else {
123 		if (prefixlen > IPV6_ABITS)
124 			return (EINVAL);
125 		bzero(mask, sizeof (struct sockaddr_in6));
126 		addr = (uint8_t *)mask;
127 		addr += offsetof(struct sockaddr_in6, sin6_addr);
128 	}
129 	mask->sa_family = af;
130 
131 	while (prefixlen > 0) {
132 		if (prefixlen >= 8) {
133 			*addr++ = 0xFF;
134 			prefixlen -= 8;
135 			continue;
136 		}
137 		*addr |= 1 << (8 - prefixlen);
138 		prefixlen--;
139 	}
140 	return (0);
141 }
142 
143 /*
144  * Convert a mask to a prefix length.
145  * Returns prefix length on success, -1 otherwise.
146  * The comments (above) for plen2mask about the use of `mask' also apply
147  * to this function and the choice to use offsetof here too.
148  */
149 int
mask2plen(const struct sockaddr * mask)150 mask2plen(const struct sockaddr *mask)
151 {
152 	int rc = 0;
153 	uint8_t last;
154 	uint8_t *addr;
155 	int limit;
156 
157 	if (mask->sa_family == AF_INET) {
158 		limit = IP_ABITS;
159 		addr = (uint8_t *)mask;
160 		addr += offsetof(struct sockaddr_in, sin_addr);
161 	} else {
162 		limit = IPV6_ABITS;
163 		addr = (uint8_t *)mask;
164 		addr += offsetof(struct sockaddr_in6, sin6_addr);
165 	}
166 
167 	while (*addr == 0xff) {
168 		rc += 8;
169 		if (rc == limit)
170 			return (limit);
171 		addr++;
172 	}
173 
174 	last = *addr;
175 	while (last != 0) {
176 		rc++;
177 		last = (last << 1) & 0xff;
178 	}
179 
180 	return (rc);
181 }
182 
183 /*
184  * Returns B_TRUE if the address in `ss' is INADDR_ANY for IPv4 or
185  * :: for IPv6. Otherwise, returns B_FALSE.
186  */
187 boolean_t
sockaddrunspec(const struct sockaddr * ss)188 sockaddrunspec(const struct sockaddr *ss)
189 {
190 	struct sockaddr_storage data;
191 
192 	switch (ss->sa_family) {
193 	case AF_INET:
194 		(void) memcpy(&data, ss, sizeof (struct sockaddr_in));
195 		return (((struct sockaddr_in *)&data)->sin_addr.s_addr ==
196 		    INADDR_ANY);
197 	case AF_INET6:
198 		(void) memcpy(&data, ss, sizeof (struct sockaddr_in6));
199 		return (IN6_IS_ADDR_UNSPECIFIED(
200 		    &((struct sockaddr_in6 *)&data)->sin6_addr));
201 	}
202 
203 	return (B_FALSE);
204 }
205