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
putbyte(uint8_t bytex,char ** posx)38 static inline void putbyte(uint8_t bytex, char **posx)
39 {
40 bool zero = false;
41 int byte = bytex, tmp, a, b;
42
43 if ((tmp = byte - 200) >= 0) {
44 *pos++ = '2';
45 zero = true;
46 byte = tmp;
47 } else if ((tmp = byte - 100) >= 0) {
48 *pos++ = '1';
49 zero = true;
50 byte = tmp;
51 }
52
53 /* make sure the compiler knows the value range of "byte" */
54 assume(byte < 100 && byte >= 0);
55
56 b = byte % 10;
57 a = byte / 10;
58 if (a || zero) {
59 *pos++ = '0' + a;
60 *pos++ = '0' + b;
61 } else
62 *pos++ = '0' + b;
63 }
64
65 static inline void puthex(uint16_t word, char **posx)
66 __attribute__((always_inline)) OPTIMIZE;
67
puthex(uint16_t word,char ** posx)68 static inline void puthex(uint16_t word, char **posx)
69 {
70 const char *digits = "0123456789abcdef";
71 if (word >= 0x1000)
72 *pos++ = digits[(word >> 12) & 0xf];
73 if (word >= 0x100)
74 *pos++ = digits[(word >> 8) & 0xf];
75 if (word >= 0x10)
76 *pos++ = digits[(word >> 4) & 0xf];
77 *pos++ = digits[word & 0xf];
78 }
79
80 #undef pos
81
82 const char *frr_inet_ntop(int af, const void * restrict src,
83 char * restrict dst, socklen_t size)
84 __attribute__((flatten)) OPTIMIZE;
85
frr_inet_ntop(int af,const void * restrict src,char * restrict dst,socklen_t size)86 const char *frr_inet_ntop(int af, const void * restrict src,
87 char * restrict dst, socklen_t size)
88 {
89 const uint8_t *b = src;
90 /* 8 * "abcd:" for IPv6
91 * note: the IPv4-embedded IPv6 syntax is only used for ::A.B.C.D,
92 * which isn't longer than 40 chars either. even with ::ffff:A.B.C.D
93 * it's shorter.
94 */
95 char buf[8 * 5], *o = buf;
96 size_t best = 0, bestlen = 0, curlen = 0, i;
97
98 switch (af) {
99 case AF_INET:
100 inet4:
101 putbyte(b[0], &o);
102 *o++ = '.';
103 putbyte(b[1], &o);
104 *o++ = '.';
105 putbyte(b[2], &o);
106 *o++ = '.';
107 putbyte(b[3], &o);
108 *o++ = '\0';
109 break;
110 case AF_INET6:
111 for (i = 0; i < 8; i++) {
112 if (b[i * 2] || b[i * 2 + 1]) {
113 if (curlen && curlen > bestlen) {
114 best = i - curlen;
115 bestlen = curlen;
116 }
117 curlen = 0;
118 continue;
119 }
120 curlen++;
121 }
122 if (curlen && curlen > bestlen) {
123 best = i - curlen;
124 bestlen = curlen;
125 }
126 /* do we want ::ffff:A.B.C.D? */
127 if (best == 0 && bestlen == 6) {
128 *o++ = ':';
129 *o++ = ':';
130 b += 12;
131 goto inet4;
132 }
133 if (bestlen == 1)
134 bestlen = 0;
135
136 for (i = 0; i < 8; i++) {
137 if (bestlen && i == best) {
138 if (i == 0)
139 *o++ = ':';
140 *o++ = ':';
141 continue;
142 }
143 if (i > best && i < best + bestlen) {
144 continue;
145 }
146 puthex((b[i * 2] << 8) | b[i * 2 + 1], &o);
147
148 if (i < 7)
149 *o++ = ':';
150 }
151 *o++ = '\0';
152 break;
153 default:
154 return NULL;
155 }
156
157 i = o - buf;
158 if (i > size)
159 return NULL;
160 /* compiler might inline memcpy if it knows the length is short,
161 * although neither gcc nor clang actually do this currently [2019]
162 */
163 assume(i <= 8 * 5);
164 memcpy(dst, buf, i);
165 return dst;
166 }
167
168 #if !defined(INET_NTOP_NO_OVERRIDE) && !defined(__APPLE__)
169 /* we want to override libc inet_ntop, but make sure it shows up in backtraces
170 * as frr_inet_ntop (to avoid confusion while debugging)
171 */
172 const char *inet_ntop(int af, const void *src, char *dst, socklen_t size)
173 __attribute__((alias ("frr_inet_ntop")));
174 #endif
175