epan/ftypes/ftype-ipv4.c

   1 /*
   2  * Wireshark - Network traffic analyzer
   3  * By Gerald Combs <gerald@wireshark.org>
   4  * Copyright 2001 Gerald Combs
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-or-later
   7  */
   8
   9 #include "config.h"
  10
  11 #include <ftypes-int.h>
  12 #include <epan/addr_resolv.h>
  13 #include <wsutil/bits_count_ones.h>
  14 #include <wsutil/strtoi.h>
  15 #include <wsutil/inet_cidr.h>
  16 #include <wsutil/array.h>
  17
  18 static void
  19 value_set_ipv4(fvalue_t *fv, const ipv4_addr_and_mask *ipv4)
  20 {
  21         fv->value.ipv4 = *ipv4;
  22 }
  23
  24 static const ipv4_addr_and_mask *
  25 value_get_ipv4(fvalue_t *fv)
  26 {
  27         return &fv->value.ipv4;
  28 }
  29
  30 static bool
  31 val_from_literal(fvalue_t *fv, const char *s, bool allow_partial_value _U_, char **err_msg)
  32 {
  33         uint32_t        addr;
  34         uint32_t nmask_bits;
  35         const char *endptr;
  36
  37         const char *slash, *net_str;
  38         const char *addr_str;
  39         char *addr_str_to_free = NULL;
  40
  41         /* Look for CIDR: Is there a single slash in the string? */
  42         slash = strchr(s, '/');
  43         if (slash) {
  44                 /* Make a copy of the string up to but not including the
  45                  * slash; that's the address portion. */
  46                 addr_str_to_free = wmem_strndup(NULL, s, slash - s);
  47                 addr_str = addr_str_to_free;
  48         }
  49         else {
  50                 addr_str = s;
  51         }
  52
  53         if (!get_host_ipaddr(addr_str, &addr)) {
  54                 if (err_msg != NULL) {
  55                         *err_msg = ws_strdup_printf("\"%s\" is not a valid hostname or IPv4 address.",
  56                             addr_str);
  57                 }
  58                 if (addr_str_to_free)
  59                         wmem_free(NULL, addr_str_to_free);
  60                 return false;
  61         }
  62
  63         if (addr_str_to_free)
  64                 wmem_free(NULL, addr_str_to_free);
  65         fv->value.ipv4.addr = g_ntohl(addr);
  66
  67         /* If CIDR, get netmask bits. */
  68         if (slash) {
  69                 /* Skip past the slash */
  70                 net_str = slash + 1;
  71
  72                 if(!ws_strtou32(net_str, &endptr, &nmask_bits) || *endptr != '\0') {
  73                         if (err_msg != NULL) {
  74                                 *err_msg = ws_strdup_printf("%s in not a valid mask", slash+1);
  75                         }
  76                         return false;
  77                 }
  78                 if (nmask_bits > 32) {
  79                         if (err_msg != NULL) {
  80                                 *err_msg = ws_strdup_printf("Netmask bits in a CIDR IPv4 address should be <= 32, not %u",
  81                                                 nmask_bits);
  82                         }
  83                         return false;
  84                 }
  85                 fv->value.ipv4.nmask = ws_ipv4_get_subnet_mask(nmask_bits);
  86         }
  87         else {
  88                 /* Not CIDR; mask covers entire address. */
  89                 fv->value.ipv4.nmask = ws_ipv4_get_subnet_mask(32);
  90         }
  91
  92         return true;
  93 }
  94
  95 static char *
  96 val_to_repr(wmem_allocator_t *scope, const fvalue_t *fv, ftrepr_t rtype _U_, int field_display _U_)
  97 {
  98         char buf[WS_INET_ADDRSTRLEN];
  99         char *repr;
 100
 101         ip_num_to_str_buf(fv->value.ipv4.addr, buf, sizeof(buf));
 102
 103         if (fv->value.ipv4.nmask != 0 && fv->value.ipv4.nmask != 0xffffffff)
 104                 repr = wmem_strdup_printf(scope, "%s/%d", buf, ws_count_ones(fv->value.ipv4.nmask));
 105         else
 106                 repr = wmem_strdup(scope, buf);
 107
 108         return repr;
 109 }
 110
 111
 112 /* Compares two ipv4_addr_and_masks, taking into account the less restrictive of the
 113  * two netmasks, applying that netmask to both addrs.
 114  *
 115  * So, for example, w.x.y.z/32 eq w.x.y.0/24 is true.
 116  */
 117
 118 static enum ft_result
 119 cmp_order(const fvalue_t *fv_a, const fvalue_t *fv_b, int *cmp)
 120 {
 121         uint32_t                addr_a, addr_b, nmask;
 122
 123         nmask = MIN(fv_a->value.ipv4.nmask, fv_b->value.ipv4.nmask);
 124         addr_a = fv_a->value.ipv4.addr & nmask;
 125         addr_b = fv_b->value.ipv4.addr & nmask;
 126         if (addr_a == addr_b)
 127                 *cmp = 0;
 128         else
 129                 *cmp = addr_a < addr_b ? -1 : 1;
 130         return FT_OK;
 131 }
 132
 133 static enum ft_result
 134 bitwise_and(fvalue_t *dst, const fvalue_t *fv_a, const fvalue_t *fv_b, char **err_ptr _U_)
 135 {
 136         dst->value.ipv4 = fv_a->value.ipv4;
 137         dst->value.ipv4.addr &= (fv_b->value.ipv4.addr & fv_b->value.ipv4.nmask);
 138         return FT_OK;
 139 }
 140
 141 static unsigned
 142 len(fvalue_t *fv _U_)
 143 {
 144         return 4;
 145 }
 146
 147 static void
 148 slice(fvalue_t *fv, GByteArray *bytes, unsigned offset, unsigned length)
 149 {
 150         uint8_t* data;
 151         uint32_t addr = g_htonl(fv->value.ipv4.addr);
 152         data = ((uint8_t*)&addr)+offset;
 153         g_byte_array_append(bytes, data, length);
 154 }
 155
 156 static unsigned
 157 ipv4_hash(const fvalue_t *fv)
 158 {
 159         int64_t val1 = fv->value.ipv4.addr;
 160         int64_t val2 = fv->value.ipv4.nmask;
 161         return g_int64_hash(&val1) ^ g_int64_hash(&val2);
 162 }
 163
 164 static bool
 165 is_zero(const fvalue_t *fv_a)
 166 {
 167         return fv_a->value.ipv4.addr == 0;
 168 }
 169
 170 void
 171 ftype_register_ipv4(void)
 172 {
 173
 174         static const ftype_t ipv4_type = {
 175                 FT_IPv4,                        /* ftype */
 176                 4,                              /* wire_size */
 177                 NULL,                           /* new_value */
 178                 NULL,                           /* copy_value */
 179                 NULL,                           /* free_value */
 180                 val_from_literal,               /* val_from_literal */
 181                 NULL,                           /* val_from_string */
 182                 NULL,                           /* val_from_charconst */
 183                 NULL,                           /* val_from_uinteger64 */
 184                 NULL,                           /* val_from_sinteger64 */
 185                 NULL,                           /* val_from_double */
 186                 val_to_repr,                    /* val_to_string_repr */
 187
 188                 NULL,                           /* val_to_uinteger64 */
 189                 NULL,                           /* val_to_sinteger64 */
 190                 NULL,                           /* val_to_double */
 191
 192                 { .set_value_ipv4 = value_set_ipv4 },   /* union set_value */
 193                 { .get_value_ipv4 = value_get_ipv4 },   /* union get_value */
 194
 195                 cmp_order,
 196                 NULL,                           /* cmp_contains */
 197                 NULL,                           /* cmp_matches */
 198
 199                 ipv4_hash,
 200                 is_zero,
 201                 NULL,
 202                 len,
 203                 (FvalueSlice)slice,
 204                 bitwise_and,
 205                 NULL,                           /* unary_minus */
 206                 NULL,                           /* add */
 207                 NULL,                           /* subtract */
 208                 NULL,                           /* multiply */
 209                 NULL,                           /* divide */
 210                 NULL,                           /* modulo */
 211         };
 212
 213         ftype_register(FT_IPv4, &ipv4_type);
 214 }
 215
 216 void
 217 ftype_register_pseudofields_ipv4(int proto)
 218 {
 219         static int hf_ft_ipv4;
 220
 221         static hf_register_info hf_ftypes[] = {
 222                 { &hf_ft_ipv4,
 223                     { "FT_IPv4", "_ws.ftypes.ipv4",
 224                         FT_IPv4, BASE_NONE, NULL, 0x00,
 225                         NULL, HFILL }
 226                 },
 227         };
 228
 229         proto_register_field_array(proto, hf_ftypes, array_length(hf_ftypes));
 230 }
 231
 232 /*
 233  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 234  *
 235  * Local variables:
 236  * c-basic-offset: 8
 237  * tab-width: 8
 238  * indent-tabs-mode: t
 239  * End:
 240  *
 241  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 242  * :indentSize=8:tabSize=8:noTabs=false:
 243  */