shemminger | 311b414 | 2005-06-23 20:25:16 +0000 | [diff] [blame] | 1 | /* |
| 2 | * em_nbyte.c N-Byte Ematch |
| 3 | * |
| 4 | * This program is free software; you can distribute it and/or |
| 5 | * modify it under the terms of the GNU General Public License |
| 6 | * as published by the Free Software Foundation; either version |
| 7 | * 2 of the License, or (at your option) any later version. |
| 8 | * |
| 9 | * Authors: Thomas Graf <tgraf@suug.ch> |
| 10 | */ |
| 11 | |
| 12 | #include <stdio.h> |
| 13 | #include <stdlib.h> |
| 14 | #include <unistd.h> |
| 15 | #include <syslog.h> |
| 16 | #include <fcntl.h> |
| 17 | #include <sys/socket.h> |
| 18 | #include <netinet/in.h> |
| 19 | #include <arpa/inet.h> |
| 20 | #include <string.h> |
| 21 | #include <dlfcn.h> |
| 22 | #include <errno.h> |
| 23 | |
| 24 | #include "m_ematch.h" |
| 25 | #include <linux/tc_ematch/tc_em_nbyte.h> |
| 26 | |
| 27 | extern struct ematch_util nbyte_ematch_util; |
| 28 | |
| 29 | static void nbyte_print_usage(FILE *fd) |
| 30 | { |
| 31 | fprintf(fd, |
| 32 | "Usage: nbyte(NEEDLE at OFFSET [layer LAYER])\n" \ |
| 33 | "where: NEEDLE := { string | \"c-escape-sequence\" }\n" \ |
| 34 | " OFFSET := int\n" \ |
| 35 | " LAYER := { link | header | next-header | 0..%d }\n" \ |
| 36 | "\n" \ |
| 37 | "Example: nbyte(\"ababa\" at 12 layer 1)\n", |
| 38 | TCF_LAYER_MAX); |
| 39 | } |
| 40 | |
| 41 | static int nbyte_parse_eopt(struct nlmsghdr *n, struct tcf_ematch_hdr *hdr, |
| 42 | struct bstr *args) |
| 43 | { |
| 44 | struct bstr *a; |
| 45 | struct bstr *needle = args; |
| 46 | unsigned long offset = 0, layer = TCF_LAYER_NETWORK; |
| 47 | int offset_present = 0; |
| 48 | struct tcf_em_nbyte nb; |
| 49 | |
| 50 | memset(&nb, 0, sizeof(nb)); |
| 51 | |
| 52 | #define PARSE_ERR(CARG, FMT, ARGS...) \ |
| 53 | em_parse_error(EINVAL, args, CARG, &nbyte_ematch_util, FMT ,##ARGS) |
| 54 | |
| 55 | if (args == NULL) |
| 56 | return PARSE_ERR(args, "nbyte: missing arguments"); |
| 57 | |
| 58 | if (needle->len <= 0) |
| 59 | return PARSE_ERR(args, "nbyte: needle length is 0"); |
| 60 | |
| 61 | for (a = bstr_next(args); a; a = bstr_next(a)) { |
| 62 | if (!bstrcmp(a, "at")) { |
| 63 | if (a->next == NULL) |
| 64 | return PARSE_ERR(a, "nbyte: missing argument"); |
| 65 | a = bstr_next(a); |
| 66 | |
| 67 | offset = bstrtoul(a); |
| 68 | if (offset == ULONG_MAX) |
| 69 | return PARSE_ERR(a, "nbyte: invalid offset, " \ |
| 70 | "must be numeric"); |
| 71 | |
| 72 | offset_present = 1; |
| 73 | } else if (!bstrcmp(a, "layer")) { |
| 74 | if (a->next == NULL) |
| 75 | return PARSE_ERR(a, "nbyte: missing argument"); |
| 76 | a = bstr_next(a); |
| 77 | |
| 78 | layer = parse_layer(a); |
| 79 | if (layer == INT_MAX) { |
| 80 | layer = bstrtoul(a); |
| 81 | if (layer == ULONG_MAX) |
| 82 | return PARSE_ERR(a, "nbyte: invalid " \ |
| 83 | "layer"); |
| 84 | } |
| 85 | |
| 86 | if (layer > TCF_LAYER_MAX) |
| 87 | return PARSE_ERR(a, "nbyte: illegal layer, " \ |
| 88 | "must be in 0..%d", TCF_LAYER_MAX); |
| 89 | } else |
| 90 | return PARSE_ERR(a, "nbyte: unknown parameter"); |
| 91 | } |
| 92 | |
| 93 | if (offset_present == 0) |
| 94 | return PARSE_ERR(a, "nbyte: offset required"); |
| 95 | |
| 96 | nb.len = needle->len; |
| 97 | nb.layer = (__u8) layer; |
| 98 | nb.off = (__u16) offset; |
| 99 | |
| 100 | addraw_l(n, MAX_MSG, hdr, sizeof(*hdr)); |
| 101 | addraw_l(n, MAX_MSG, &nb, sizeof(nb)); |
| 102 | addraw_l(n, MAX_MSG, needle->data, needle->len); |
| 103 | |
| 104 | #undef PARSE_ERR |
| 105 | return 0; |
| 106 | } |
| 107 | |
| 108 | static int nbyte_print_eopt(FILE *fd, struct tcf_ematch_hdr *hdr, void *data, |
| 109 | int data_len) |
| 110 | { |
| 111 | int i; |
| 112 | struct tcf_em_nbyte *nb = data; |
| 113 | __u8 *needle; |
| 114 | |
| 115 | if (data_len < sizeof(*nb)) { |
| 116 | fprintf(stderr, "NByte header size mismatch\n"); |
| 117 | return -1; |
| 118 | } |
| 119 | |
| 120 | if (data_len < sizeof(*nb) + nb->len) { |
| 121 | fprintf(stderr, "NByte payload size mismatch\n"); |
| 122 | return -1; |
| 123 | } |
| 124 | |
| 125 | needle = data + sizeof(*nb); |
| 126 | |
| 127 | for (i = 0; i < nb->len; i++) |
| 128 | fprintf(fd, "%02x ", needle[i]); |
| 129 | |
| 130 | fprintf(fd, "\""); |
| 131 | for (i = 0; i < nb->len; i++) |
| 132 | fprintf(fd, "%c", isprint(needle[i]) ? needle[i] : '.'); |
| 133 | fprintf(fd, "\" at %d layer %d", nb->off, nb->layer); |
| 134 | |
| 135 | return 0; |
| 136 | } |
| 137 | |
| 138 | struct ematch_util nbyte_ematch_util = { |
| 139 | .kind = "nbyte", |
| 140 | .kind_num = TCF_EM_NBYTE, |
| 141 | .parse_eopt = nbyte_parse_eopt, |
| 142 | .print_eopt = nbyte_print_eopt, |
| 143 | .print_usage = nbyte_print_usage |
| 144 | }; |