diff options
Diffstat (limited to 'lib/in46_addr.c')
| -rw-r--r-- | lib/in46_addr.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/lib/in46_addr.c b/lib/in46_addr.c new file mode 100644 index 0000000..903ceec --- /dev/null +++ b/lib/in46_addr.c @@ -0,0 +1,148 @@ +/* + * IPv4/v6 address functions. + * Copyright (C) 2017 by Harald Welte <laforge@gnumonks.org> + * + * The contents of this file may be used under the terms of the GNU + * General Public License Version 2, provided that the above copyright + * notice and this permission notice is included in all copies or + * substantial portions of the software. + * + */ + +#include "../lib/in46_addr.h" + +#include <sys/types.h> +#include <netinet/in.h> +#include <sys/socket.h> +#include <arpa/inet.h> +#include <netdb.h> +#include <stdlib.h> +#include <string.h> + +/*! Return the address family of given \reff in46_addr argument */ +int in46a_to_af(const struct in46_addr *in) +{ + switch (in->len) { + case 4: + return AF_INET; + case 16: + return AF_INET6; + default: + return -1; + } +} + +/*! Convert \ref in46_addr to sockaddr_storage */ +int in46a_to_sas(struct sockaddr_storage *out, const struct in46_addr *in) +{ + struct sockaddr_in *sin = (struct sockaddr_in *)out; + struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)out; + + switch (in->len) { + case 4: + sin->sin_family = AF_INET; + sin->sin_addr = in->v4; + break; + case 16: + sin6->sin6_family = AF_INET; + sin6->sin6_addr = in->v6; + break; + default: + return -1; + } + + return 0; +} + +/*! Convenience wrapper around inet_ntop() for \ref in46_addr */ +const char *in46a_ntop(const struct in46_addr *in, char *dst, socklen_t dst_size) +{ + int af = in46a_to_af(in); + if (af < 0) + return NULL; + + return inet_ntop(af, (const void *) &in->v4, dst, dst_size); +} + +/*! Determine if two in46_addr are equal or not + * \returns 1 in case they are equal; 0 otherwise */ +int in46a_equal(const struct in46_addr *a, const struct in46_addr *b) +{ + if (a->len == b->len && !memcmp(&a->v6, &b->v6, a->len)) + return 1; + else + return 0; +} + +/*! Match if IPv6 addr1 + addr2 are within same \a mask */ +static int ipv6_within_mask(const struct in6_addr *addr1, const struct in6_addr *addr2, + const struct in6_addr *mask) +{ + struct in6_addr masked = *addr2; +#if defined(__linux__) + masked.s6_addr32[0] &= mask->s6_addr32[0]; + masked.s6_addr32[1] &= mask->s6_addr32[1]; + masked.s6_addr32[2] &= mask->s6_addr32[2]; + masked.s6_addr32[3] &= mask->s6_addr32[3]; +#else + masked.__u6_addr.__u6_addr32[0] &= mask->__u6_addr.__u6_addr32[0]; + masked.__u6_addr.__u6_addr32[1] &= mask->__u6_addr.__u6_addr32[1]; + masked.__u6_addr.__u6_addr32[2] &= mask->__u6_addr.__u6_addr32[2]; + masked.__u6_addr.__u6_addr32[3] &= mask->__u6_addr.__u6_addr32[3]; +#endif + if (!memcmp(addr1, &masked, sizeof(struct in6_addr))) + return 1; + else + return 0; +} + +/*! Create an IPv6 netmask from the given prefix length */ +static void create_ipv6_netmask(struct in6_addr *netmask, int prefixlen) +{ + uint32_t *p_netmask; + memset(netmask, 0, sizeof(struct in6_addr)); + if (prefixlen < 0) + prefixlen = 0; + else if (128 < prefixlen) + prefixlen = 128; + +#if defined(__linux__) + p_netmask = &netmask->s6_addr32[0]; +#else + p_netmask = &netmask->__u6_addr.__u6_addr32[0]; +#endif + while (32 < prefixlen) { + *p_netmask = 0xffffffff; + p_netmask++; + prefixlen -= 32; + } + if (prefixlen != 0) { + *p_netmask = htonl(0xFFFFFFFF << (32 - prefixlen)); + } +} + +/*! Determine if given \a addr is within given \a net + \a prefixlen + * Builds the netmask from \a net + \a prefixlen and matches it to \a addr + * \returns 1 in case of a match, 0 otherwise */ +int in46a_within_mask(const struct in46_addr *addr, const struct in46_addr *net, size_t prefixlen) +{ + struct in_addr netmask; + struct in6_addr netmask6; + + if (addr->len != net->len) + return 0; + + switch (addr->len) { + case 4: + netmask.s_addr = htonl(0xFFFFFFFF << (32 - prefixlen)); + if ((addr->v4.s_addr & netmask.s_addr) == net->v4.s_addr) + return 1; + else + return 0; + case 16: + create_ipv6_netmask(&netmask6, prefixlen); + return ipv6_within_mask(&addr->v6, &net->v6, &netmask6); + default: + return 0; + } +} |