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1 /**
2  * @file
3  * This is the IPv4 address tools implementation.
4  *
5  */
6 
7 /*
8  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without modification,
12  * are permitted provided that the following conditions are met:
13  *
14  * 1. Redistributions of source code must retain the above copyright notice,
15  *    this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright notice,
17  *    this list of conditions and the following disclaimer in the documentation
18  *    and/or other materials provided with the distribution.
19  * 3. The name of the author may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
23  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
25  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
26  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
27  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
30  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
31  * OF SUCH DAMAGE.
32  *
33  * This file is part of the lwIP TCP/IP stack.
34  *
35  * Author: Adam Dunkels <adam@sics.se>
36  *
37  */
38 
39 #include "lwip/opt.h"
40 #include "lwip/ip_addr.h"
41 #include "lwip/netif.h"
42 
43 /* used by IP_ADDR_ANY and IP_ADDR_BROADCAST in ip_addr.h */
44 const ip_addr_t ip_addr_any = { IPADDR_ANY };
45 const ip_addr_t ip_addr_broadcast = { IPADDR_BROADCAST };
46 
47 /**
48  * Determine if an address is a broadcast address on a network interface
49  *
50  * @param addr address to be checked
51  * @param netif the network interface against which the address is checked
52  * @return returns non-zero if the address is a broadcast address
53  */
54 u8_t
ip4_addr_isbroadcast(u32_t addr,const struct netif * netif)55 ip4_addr_isbroadcast(u32_t addr, const struct netif *netif)
56 {
57   ip_addr_t ipaddr;
58   ip4_addr_set_u32(&ipaddr, addr);
59 
60   /* all ones (broadcast) or all zeroes (old skool broadcast) */
61   if ((~addr == IPADDR_ANY) ||
62       (addr == IPADDR_ANY)) {
63     return 1;
64   /* no broadcast support on this network interface? */
65   } else if ((netif->flags & NETIF_FLAG_BROADCAST) == 0) {
66     /* the given address cannot be a broadcast address
67      * nor can we check against any broadcast addresses */
68     return 0;
69   /* address matches network interface address exactly? => no broadcast */
70   } else if (addr == ip4_addr_get_u32(&netif->ip_addr)) {
71     return 0;
72   /*  on the same (sub) network... */
73   } else if (ip_addr_netcmp(&ipaddr, &(netif->ip_addr), &(netif->netmask))
74          /* ...and host identifier bits are all ones? =>... */
75           && ((addr & ~ip4_addr_get_u32(&netif->netmask)) ==
76            (IPADDR_BROADCAST & ~ip4_addr_get_u32(&netif->netmask)))) {
77     /* => network broadcast address */
78     return 1;
79   } else {
80     return 0;
81   }
82 }
83 
84 /** Checks if a netmask is valid (starting with ones, then only zeros)
85  *
86  * @param netmask the IPv4 netmask to check (in network byte order!)
87  * @return 1 if the netmask is valid, 0 if it is not
88  */
89 u8_t
ip4_addr_netmask_valid(u32_t netmask)90 ip4_addr_netmask_valid(u32_t netmask)
91 {
92   u32_t mask;
93   u32_t nm_hostorder = lwip_htonl(netmask);
94 
95   /* first, check for the first zero */
96   for (mask = 1UL << 31 ; mask != 0; mask >>= 1) {
97     if ((nm_hostorder & mask) == 0) {
98       break;
99     }
100   }
101   /* then check that there is no one */
102   for (; mask != 0; mask >>= 1) {
103     if ((nm_hostorder & mask) != 0) {
104       /* there is a one after the first zero -> invalid */
105       return 0;
106     }
107   }
108   /* no one after the first zero -> valid */
109   return 1;
110 }
111 
112 /* Here for now until needed in other places in lwIP */
113 #ifndef isprint
114 #define in_range(c, lo, up)  ((u8_t)c >= lo && (u8_t)c <= up)
115 #define isprint(c)           in_range(c, 0x20, 0x7f)
116 #define isdigit(c)           in_range(c, '0', '9')
117 #define isxdigit(c)          (isdigit(c) || in_range(c, 'a', 'f') || in_range(c, 'A', 'F'))
118 #define islower(c)           in_range(c, 'a', 'z')
119 #define isspace(c)           (c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v')
120 #endif
121 
122 /**
123  * Ascii internet address interpretation routine.
124  * The value returned is in network order.
125  *
126  * @param cp IP address in ascii represenation (e.g. "127.0.0.1")
127  * @return ip address in network order
128  */
129 u32_t
ipaddr_addr(const char * cp)130 ipaddr_addr(const char *cp)
131 {
132   ip_addr_t val;
133 
134   if (ipaddr_aton(cp, &val)) {
135     return ip4_addr_get_u32(&val);
136   }
137   return (IPADDR_NONE);
138 }
139 
140 /**
141  * Check whether "cp" is a valid ascii representation
142  * of an Internet address and convert to a binary address.
143  * Returns 1 if the address is valid, 0 if not.
144  * This replaces inet_addr, the return value from which
145  * cannot distinguish between failure and a local broadcast address.
146  *
147  * @param cp IP address in ascii represenation (e.g. "127.0.0.1")
148  * @param addr pointer to which to save the ip address in network order
149  * @return 1 if cp could be converted to addr, 0 on failure
150  */
151 int
ipaddr_aton(const char * cp,ip_addr_t * addr)152 ipaddr_aton(const char *cp, ip_addr_t *addr)
153 {
154   u32_t val;
155   u8_t base;
156   char c;
157   u32_t parts[4];
158   u32_t *pp = parts;
159 
160   c = *cp;
161   for (;;) {
162     /*
163      * Collect number up to ``.''.
164      * Values are specified as for C:
165      * 0x=hex, 0=octal, 1-9=decimal.
166      */
167     if (!isdigit(c))
168       return (0);
169     val = 0;
170     base = 10;
171     if (c == '0') {
172       c = *++cp;
173       if (c == 'x' || c == 'X') {
174         base = 16;
175         c = *++cp;
176       } else
177         base = 8;
178     }
179     for (;;) {
180       if (isdigit(c)) {
181         val = (val * base) + (int)(c - '0');
182         c = *++cp;
183       } else if (base == 16 && isxdigit(c)) {
184         val = (val << 4) | (int)(c + 10 - (islower(c) ? 'a' : 'A'));
185         c = *++cp;
186       } else
187         break;
188     }
189     if (c == '.') {
190       /*
191        * Internet format:
192        *  a.b.c.d
193        *  a.b.c   (with c treated as 16 bits)
194        *  a.b (with b treated as 24 bits)
195        */
196       if (pp >= parts + 3) {
197         return (0);
198       }
199       *pp++ = val;
200       c = *++cp;
201     } else
202       break;
203   }
204   /*
205    * Check for trailing characters.
206    */
207   if (c != '\0' && !isspace(c)) {
208     return (0);
209   }
210   /*
211    * Concoct the address according to
212    * the number of parts specified.
213    */
214   switch (pp - parts + 1) {
215 
216   case 0:
217     return (0);       /* initial nondigit */
218 
219   case 1:             /* a -- 32 bits */
220     break;
221 
222   case 2:             /* a.b -- 8.24 bits */
223     if (val > 0xffffffUL) {
224       return (0);
225     }
226     val |= parts[0] << 24;
227     break;
228 
229   case 3:             /* a.b.c -- 8.8.16 bits */
230     if (val > 0xffff) {
231       return (0);
232     }
233     val |= (parts[0] << 24) | (parts[1] << 16);
234     break;
235 
236   case 4:             /* a.b.c.d -- 8.8.8.8 bits */
237     if (val > 0xff) {
238       return (0);
239     }
240     val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
241     break;
242   default:
243     LWIP_ASSERT("unhandled", 0);
244     break;
245   }
246   if (addr) {
247     ip4_addr_set_u32(addr, htonl(val));
248   }
249   return (1);
250 }
251 
252 /**
253  * Convert numeric IP address into decimal dotted ASCII representation.
254  * returns ptr to static buffer; not reentrant!
255  *
256  * @param addr ip address in network order to convert
257  * @return pointer to a global static (!) buffer that holds the ASCII
258  *         represenation of addr
259  */
260 char *
ipaddr_ntoa(const ip_addr_t * addr)261 ipaddr_ntoa(const ip_addr_t *addr)
262 {
263   static char str[16];
264   return ipaddr_ntoa_r(addr, str, 16);
265 }
266 
267 /**
268  * Same as ipaddr_ntoa, but reentrant since a user-supplied buffer is used.
269  *
270  * @param addr ip address in network order to convert
271  * @param buf target buffer where the string is stored
272  * @param buflen length of buf
273  * @return either pointer to buf which now holds the ASCII
274  *         representation of addr or NULL if buf was too small
275  */
ipaddr_ntoa_r(const ip_addr_t * addr,char * buf,int buflen)276 char *ipaddr_ntoa_r(const ip_addr_t *addr, char *buf, int buflen)
277 {
278   u32_t s_addr;
279   char inv[3];
280   char *rp;
281   u8_t *ap;
282   u8_t rem;
283   u8_t n;
284   u8_t i;
285   int len = 0;
286 
287   s_addr = ip4_addr_get_u32(addr);
288 
289   rp = buf;
290   ap = (u8_t *)&s_addr;
291   for(n = 0; n < 4; n++) {
292     i = 0;
293     do {
294       rem = *ap % (u8_t)10;
295       *ap /= (u8_t)10;
296       inv[i++] = '0' + rem;
297     } while(*ap);
298     while(i--) {
299       if (len++ >= buflen) {
300         return NULL;
301       }
302       *rp++ = inv[i];
303     }
304     if (len++ >= buflen) {
305       return NULL;
306     }
307     *rp++ = '.';
308     ap++;
309   }
310   *--rp = 0;
311   return buf;
312 }
313