diff options
Diffstat (limited to 'lib/ntop.c')
| -rw-r--r-- | lib/ntop.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/lib/ntop.c b/lib/ntop.c new file mode 100644 index 0000000..1b2dd7a --- /dev/null +++ b/lib/ntop.c @@ -0,0 +1,178 @@ +/* + * optimized ntop, about 10x faster than libc versions [as of 2019] + * + * Copyright (c) 2019 David Lamparter, for NetDEF, Inc. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <stdio.h> +#include <stdint.h> +#include <stdbool.h> +#include <string.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> + +#include "compiler.h" + +#define pos (*posx) + +static inline void putbyte(uint8_t bytex, char **posx) + __attribute__((always_inline)) OPTIMIZE; + +static inline void putbyte(uint8_t bytex, char **posx) +{ + bool zero = false; + int byte = bytex, tmp, a, b; + + tmp = byte - 200; + if (tmp >= 0) { + *pos++ = '2'; + zero = true; + byte = tmp; + } else { + tmp = byte - 100; + if (tmp >= 0) { + *pos++ = '1'; + zero = true; + byte = tmp; + } + } + + /* make sure the compiler knows the value range of "byte" */ + assume(byte < 100 && byte >= 0); + + b = byte % 10; + a = byte / 10; + if (a || zero) { + *pos++ = '0' + a; + *pos++ = '0' + b; + } else + *pos++ = '0' + b; +} + +static inline void puthex(uint16_t word, char **posx) + __attribute__((always_inline)) OPTIMIZE; + +static inline void puthex(uint16_t word, char **posx) +{ + const char *digits = "0123456789abcdef"; + if (word >= 0x1000) + *pos++ = digits[(word >> 12) & 0xf]; + if (word >= 0x100) + *pos++ = digits[(word >> 8) & 0xf]; + if (word >= 0x10) + *pos++ = digits[(word >> 4) & 0xf]; + *pos++ = digits[word & 0xf]; +} + +#undef pos + +const char *frr_inet_ntop(int af, const void * restrict src, + char * restrict dst, socklen_t size) + __attribute__((flatten)) OPTIMIZE; + +const char *frr_inet_ntop(int af, const void * restrict src, + char * restrict dst, socklen_t size) +{ + const uint8_t *b = src; + /* 8 * "abcd:" for IPv6 + * note: the IPv4-embedded IPv6 syntax is only used for ::A.B.C.D, + * which isn't longer than 40 chars either. even with ::ffff:A.B.C.D + * it's shorter. + */ + char buf[8 * 5], *o = buf; + size_t best = 0, bestlen = 0, curlen = 0, i; + + switch (af) { + case AF_INET: +inet4: + putbyte(b[0], &o); + *o++ = '.'; + putbyte(b[1], &o); + *o++ = '.'; + putbyte(b[2], &o); + *o++ = '.'; + putbyte(b[3], &o); + *o++ = '\0'; + break; + case AF_INET6: + for (i = 0; i < 8; i++) { + if (b[i * 2] || b[i * 2 + 1]) { + if (curlen && curlen > bestlen) { + best = i - curlen; + bestlen = curlen; + } + curlen = 0; + continue; + } + curlen++; + } + if (curlen && curlen > bestlen) { + best = i - curlen; + bestlen = curlen; + } + /* do we want ::ffff:A.B.C.D? */ + if (best == 0 && bestlen == 6) { + *o++ = ':'; + *o++ = ':'; + b += 12; + goto inet4; + } + if (bestlen == 1) + bestlen = 0; + + for (i = 0; i < 8; i++) { + if (bestlen && i == best) { + if (i == 0) + *o++ = ':'; + *o++ = ':'; + continue; + } + if (i > best && i < best + bestlen) { + continue; + } + puthex((b[i * 2] << 8) | b[i * 2 + 1], &o); + + if (i < 7) + *o++ = ':'; + } + *o++ = '\0'; + break; + default: + return NULL; + } + + i = o - buf; + if (i > size) + return NULL; + /* compiler might inline memcpy if it knows the length is short, + * although neither gcc nor clang actually do this currently [2019] + */ + assume(i <= 8 * 5); + memcpy(dst, buf, i); + return dst; +} + +#if !defined(INET_NTOP_NO_OVERRIDE) && !defined(__APPLE__) +/* we want to override libc inet_ntop, but make sure it shows up in backtraces + * as frr_inet_ntop (to avoid confusion while debugging) + */ +const char *inet_ntop(int af, const void *src, char *dst, socklen_t size) + __attribute__((alias ("frr_inet_ntop"))); +#endif |