1 /* $OpenBSD: tcpdrop.c,v 1.18 2018/11/08 07:14:37 mestre 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 36 __dead void usage(void); 37 38 __dead void 39 usage(void) 40 { 41 extern char *__progname; 42 43 fprintf(stderr, 44 "usage: %s local-addr local-port remote-addr remote-port\n", 45 __progname); 46 fprintf(stderr, 47 " %s local-addr:local-port remote-addr:remote-port\n", 48 __progname); 49 exit(1); 50 } 51 52 /* 53 * Drop a tcp connection. 54 */ 55 int 56 main(int argc, char **argv) 57 { 58 int mib[] = { CTL_NET, PF_INET, IPPROTO_TCP, TCPCTL_DROP }; 59 struct addrinfo hints, *ail, *aif, *laddr, *faddr; 60 char fhbuf[NI_MAXHOST], fsbuf[NI_MAXSERV]; 61 char lhbuf[NI_MAXHOST], lsbuf[NI_MAXSERV]; 62 char *laddr1, *addr1, *port1, *faddr2, *addr2, *port2; 63 struct tcp_ident_mapping tir; 64 int gaierr, rval = 0; 65 66 if (unveil("/etc/hosts", "r") == -1) 67 err(1, "unveil"); 68 if (unveil("/etc/resolv.conf", "r") == -1) 69 err(1, "unveil"); 70 if (unveil(NULL, NULL) == -1) 71 err(1, "unveil"); 72 73 memset(&hints, 0, sizeof(hints)); 74 hints.ai_family = AF_UNSPEC; 75 hints.ai_socktype = SOCK_STREAM; 76 77 if (argc == 3) { 78 laddr1 = addr1 = strdup(argv[1]); 79 if (!addr1) 80 err(1, "strdup"); 81 port1 = strrchr(addr1, ':'); 82 if (port1) 83 *port1++ = '\0'; 84 else 85 usage(); 86 87 faddr2 = addr2 = strdup(argv[2]); 88 if (!addr2) 89 err(1, "strdup"); 90 port2 = strrchr(addr2, ':'); 91 if (port2) 92 *port2++ = '\0'; 93 else 94 usage(); 95 } else if (argc == 5) { 96 laddr1 = addr1 = argv[1]; 97 port1 = argv[2]; 98 faddr2 = addr2 = argv[3]; 99 port2 = argv[4]; 100 } else 101 usage(); 102 103 if (addr1[0] == '[' && addr1[strlen(addr1) - 1] == ']') { 104 laddr1 = strdup(addr1); 105 if (!laddr1) 106 err(1, "strdup"); 107 laddr1[strlen(laddr1) - 1] = '\0'; 108 laddr1++; 109 } 110 if (addr2[0] == '[' && addr2[strlen(addr2) - 1] == ']') { 111 faddr2 = strdup(addr2); 112 if (!faddr2) 113 err(1, "strdup"); 114 faddr2[strlen(faddr2) - 1] = '\0'; 115 faddr2++; 116 } 117 118 if ((gaierr = getaddrinfo(laddr1, port1, &hints, &laddr)) != 0) 119 errx(1, "%s port %s: %s", addr1, port1, 120 gai_strerror(gaierr)); 121 122 if ((gaierr = getaddrinfo(faddr2, port2, &hints, &faddr)) != 0) 123 errx(1, "%s port %s: %s", addr2, port2, 124 gai_strerror(gaierr)); 125 126 rval = 1; 127 for (ail = laddr; ail; ail = ail->ai_next) { 128 for (aif = faddr; aif; aif = aif->ai_next) { 129 if (ail->ai_family != aif->ai_family) 130 continue; 131 rval = 0; 132 memset(&tir, 0, sizeof(tir)); 133 memcpy(&tir.faddr, aif->ai_addr, aif->ai_addrlen); 134 memcpy(&tir.laddr, ail->ai_addr, ail->ai_addrlen); 135 136 if ((gaierr = getnameinfo(aif->ai_addr, aif->ai_addrlen, 137 fhbuf, sizeof(fhbuf), fsbuf, sizeof(fsbuf), 138 NI_NUMERICHOST | NI_NUMERICSERV)) != 0) 139 errx(1, "getnameinfo: %s", gai_strerror(gaierr)); 140 if ((gaierr = getnameinfo(ail->ai_addr, ail->ai_addrlen, 141 lhbuf, sizeof(lhbuf), lsbuf, sizeof(lsbuf), 142 NI_NUMERICHOST | NI_NUMERICSERV)) != 0) 143 errx(1, "getnameinfo: %s", gai_strerror(gaierr)); 144 145 if (sysctl(mib, sizeof (mib) / sizeof (int), NULL, 146 NULL, &tir, sizeof(tir)) == -1) { 147 rval = 1; 148 warn("%s %s %s %s", lhbuf, lsbuf, fhbuf, fsbuf); 149 } else { 150 if (aif->ai_family == PF_INET6) 151 printf("[%s]:%s [%s]:%s dropped\n", 152 lhbuf, lsbuf, fhbuf, fsbuf); 153 else 154 printf("%s:%s %s:%s dropped\n", 155 lhbuf, lsbuf, fhbuf, fsbuf); 156 } 157 } 158 } 159 freeaddrinfo(laddr); 160 freeaddrinfo(faddr); 161 exit(rval); 162 } 163