1 /* $OpenBSD: tcpdrop.c,v 1.19 2019/11/27 17:49:09 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 2004 Markus Friedl <markus@openbsd.org> 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 #include <sys/socket.h> 20 #include <sys/sysctl.h> 21 #include <sys/queue.h> 22 #include <sys/timeout.h> 23 24 #include <netinet/in.h> 25 #include <netinet/tcp.h> 26 #include <netinet/tcp_timer.h> 27 #include <netinet/tcp_var.h> 28 29 #include <err.h> 30 #include <netdb.h> 31 #include <stdio.h> 32 #include <string.h> 33 #include <stdlib.h> 34 #include <unistd.h> 35 #include <resolv.h> 36 37 __dead void usage(void); 38 39 __dead void 40 usage(void) 41 { 42 extern char *__progname; 43 44 fprintf(stderr, 45 "usage: %s local-addr local-port remote-addr remote-port\n", 46 __progname); 47 fprintf(stderr, 48 " %s local-addr:local-port remote-addr:remote-port\n", 49 __progname); 50 exit(1); 51 } 52 53 /* 54 * Drop a tcp connection. 55 */ 56 int 57 main(int argc, char **argv) 58 { 59 int mib[] = { CTL_NET, PF_INET, IPPROTO_TCP, TCPCTL_DROP }; 60 struct addrinfo hints, *ail, *aif, *laddr, *faddr; 61 char fhbuf[NI_MAXHOST], fsbuf[NI_MAXSERV]; 62 char lhbuf[NI_MAXHOST], lsbuf[NI_MAXSERV]; 63 char *laddr1, *addr1, *port1, *faddr2, *addr2, *port2; 64 struct tcp_ident_mapping tir; 65 int gaierr, rval = 0; 66 67 if (unveil(_PATH_HOSTS, "r") == -1) 68 err(1, "unveil"); 69 if (unveil(_PATH_RESCONF, "r") == -1) 70 err(1, "unveil"); 71 if (unveil(NULL, NULL) == -1) 72 err(1, "unveil"); 73 74 memset(&hints, 0, sizeof(hints)); 75 hints.ai_family = AF_UNSPEC; 76 hints.ai_socktype = SOCK_STREAM; 77 78 if (argc == 3) { 79 laddr1 = addr1 = strdup(argv[1]); 80 if (!addr1) 81 err(1, "strdup"); 82 port1 = strrchr(addr1, ':'); 83 if (port1) 84 *port1++ = '\0'; 85 else 86 usage(); 87 88 faddr2 = addr2 = strdup(argv[2]); 89 if (!addr2) 90 err(1, "strdup"); 91 port2 = strrchr(addr2, ':'); 92 if (port2) 93 *port2++ = '\0'; 94 else 95 usage(); 96 } else if (argc == 5) { 97 laddr1 = addr1 = argv[1]; 98 port1 = argv[2]; 99 faddr2 = addr2 = argv[3]; 100 port2 = argv[4]; 101 } else 102 usage(); 103 104 if (addr1[0] == '[' && addr1[strlen(addr1) - 1] == ']') { 105 laddr1 = strdup(addr1); 106 if (!laddr1) 107 err(1, "strdup"); 108 laddr1[strlen(laddr1) - 1] = '\0'; 109 laddr1++; 110 } 111 if (addr2[0] == '[' && addr2[strlen(addr2) - 1] == ']') { 112 faddr2 = strdup(addr2); 113 if (!faddr2) 114 err(1, "strdup"); 115 faddr2[strlen(faddr2) - 1] = '\0'; 116 faddr2++; 117 } 118 119 if ((gaierr = getaddrinfo(laddr1, port1, &hints, &laddr)) != 0) 120 errx(1, "%s port %s: %s", addr1, port1, 121 gai_strerror(gaierr)); 122 123 if ((gaierr = getaddrinfo(faddr2, port2, &hints, &faddr)) != 0) 124 errx(1, "%s port %s: %s", addr2, port2, 125 gai_strerror(gaierr)); 126 127 rval = 1; 128 for (ail = laddr; ail; ail = ail->ai_next) { 129 for (aif = faddr; aif; aif = aif->ai_next) { 130 if (ail->ai_family != aif->ai_family) 131 continue; 132 rval = 0; 133 memset(&tir, 0, sizeof(tir)); 134 memcpy(&tir.faddr, aif->ai_addr, aif->ai_addrlen); 135 memcpy(&tir.laddr, ail->ai_addr, ail->ai_addrlen); 136 137 if ((gaierr = getnameinfo(aif->ai_addr, aif->ai_addrlen, 138 fhbuf, sizeof(fhbuf), fsbuf, sizeof(fsbuf), 139 NI_NUMERICHOST | NI_NUMERICSERV)) != 0) 140 errx(1, "getnameinfo: %s", gai_strerror(gaierr)); 141 if ((gaierr = getnameinfo(ail->ai_addr, ail->ai_addrlen, 142 lhbuf, sizeof(lhbuf), lsbuf, sizeof(lsbuf), 143 NI_NUMERICHOST | NI_NUMERICSERV)) != 0) 144 errx(1, "getnameinfo: %s", gai_strerror(gaierr)); 145 146 if (sysctl(mib, sizeof (mib) / sizeof (int), NULL, 147 NULL, &tir, sizeof(tir)) == -1) { 148 rval = 1; 149 warn("%s %s %s %s", lhbuf, lsbuf, fhbuf, fsbuf); 150 } else { 151 if (aif->ai_family == PF_INET6) 152 printf("[%s]:%s [%s]:%s dropped\n", 153 lhbuf, lsbuf, fhbuf, fsbuf); 154 else 155 printf("%s:%s %s:%s dropped\n", 156 lhbuf, lsbuf, fhbuf, fsbuf); 157 } 158 } 159 } 160 freeaddrinfo(laddr); 161 freeaddrinfo(faddr); 162 exit(rval); 163 } 164