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Merge pull request #13278 from FRRouting/mergify/bp/stable/8.5/pr-13269
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1 /*
2 * optimized ntop, about 10x faster than libc versions [as of 2019]
3 *
4 * Copyright (c) 2019 David Lamparter, for NetDEF, Inc.
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #ifdef HAVE_CONFIG_H
20 #include "config.h"
21 #endif
22
23 #include <stdio.h>
24 #include <stdint.h>
25 #include <stdbool.h>
26 #include <string.h>
27 #include <sys/socket.h>
28 #include <netinet/in.h>
29 #include <arpa/inet.h>
30
31 #include "compiler.h"
32
33 #define pos (*posx)
34
35 static inline void putbyte(uint8_t bytex, char **posx)
36 __attribute__((always_inline)) OPTIMIZE;
37
38 static inline void putbyte(uint8_t bytex, char **posx)
39 {
40 bool zero = false;
41 int byte = bytex, tmp, a, b;
42
43 tmp = byte - 200;
44 if (tmp >= 0) {
45 *pos++ = '2';
46 zero = true;
47 byte = tmp;
48 } else {
49 tmp = byte - 100;
50 if (tmp >= 0) {
51 *pos++ = '1';
52 zero = true;
53 byte = tmp;
54 }
55 }
56
57 /* make sure the compiler knows the value range of "byte" */
58 assume(byte < 100 && byte >= 0);
59
60 b = byte % 10;
61 a = byte / 10;
62 if (a || zero) {
63 *pos++ = '0' + a;
64 *pos++ = '0' + b;
65 } else
66 *pos++ = '0' + b;
67 }
68
69 static inline void puthex(uint16_t word, char **posx)
70 __attribute__((always_inline)) OPTIMIZE;
71
72 static inline void puthex(uint16_t word, char **posx)
73 {
74 const char *digits = "0123456789abcdef";
75 if (word >= 0x1000)
76 *pos++ = digits[(word >> 12) & 0xf];
77 if (word >= 0x100)
78 *pos++ = digits[(word >> 8) & 0xf];
79 if (word >= 0x10)
80 *pos++ = digits[(word >> 4) & 0xf];
81 *pos++ = digits[word & 0xf];
82 }
83
84 #undef pos
85
86 const char *frr_inet_ntop(int af, const void * restrict src,
87 char * restrict dst, socklen_t size)
88 __attribute__((flatten)) OPTIMIZE;
89
90 const char *frr_inet_ntop(int af, const void * restrict src,
91 char * restrict dst, socklen_t size)
92 {
93 const uint8_t *b = src;
94 /* 8 * "abcd:" for IPv6
95 * note: the IPv4-embedded IPv6 syntax is only used for ::A.B.C.D,
96 * which isn't longer than 40 chars either. even with ::ffff:A.B.C.D
97 * it's shorter.
98 */
99 char buf[8 * 5], *o = buf;
100 size_t best = 0, bestlen = 0, curlen = 0, i;
101
102 switch (af) {
103 case AF_INET:
104 inet4:
105 putbyte(b[0], &o);
106 *o++ = '.';
107 putbyte(b[1], &o);
108 *o++ = '.';
109 putbyte(b[2], &o);
110 *o++ = '.';
111 putbyte(b[3], &o);
112 *o++ = '\0';
113 break;
114 case AF_INET6:
115 for (i = 0; i < 8; i++) {
116 if (b[i * 2] || b[i * 2 + 1]) {
117 if (curlen && curlen > bestlen) {
118 best = i - curlen;
119 bestlen = curlen;
120 }
121 curlen = 0;
122 continue;
123 }
124 curlen++;
125 }
126 if (curlen && curlen > bestlen) {
127 best = i - curlen;
128 bestlen = curlen;
129 }
130 /* do we want ::ffff:A.B.C.D? */
131 if (best == 0 && bestlen == 6) {
132 *o++ = ':';
133 *o++ = ':';
134 b += 12;
135 goto inet4;
136 }
137 if (bestlen == 1)
138 bestlen = 0;
139
140 for (i = 0; i < 8; i++) {
141 if (bestlen && i == best) {
142 if (i == 0)
143 *o++ = ':';
144 *o++ = ':';
145 continue;
146 }
147 if (i > best && i < best + bestlen) {
148 continue;
149 }
150 puthex((b[i * 2] << 8) | b[i * 2 + 1], &o);
151
152 if (i < 7)
153 *o++ = ':';
154 }
155 *o++ = '\0';
156 break;
157 default:
158 return NULL;
159 }
160
161 i = o - buf;
162 if (i > size)
163 return NULL;
164 /* compiler might inline memcpy if it knows the length is short,
165 * although neither gcc nor clang actually do this currently [2019]
166 */
167 assume(i <= 8 * 5);
168 memcpy(dst, buf, i);
169 return dst;
170 }
171
172 #if !defined(INET_NTOP_NO_OVERRIDE) && !defined(__APPLE__)
173 /* we want to override libc inet_ntop, but make sure it shows up in backtraces
174 * as frr_inet_ntop (to avoid confusion while debugging)
175 */
176 const char *inet_ntop(int af, const void *src, char *dst, socklen_t size)
177 __attribute__((alias ("frr_inet_ntop")));
178 #endif