diff options
Diffstat (limited to 'inet/inet6_rth.c')
| -rw-r--r-- | inet/inet6_rth.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/inet/inet6_rth.c b/inet/inet6_rth.c new file mode 100644 index 0000000..15f8240 --- /dev/null +++ b/inet/inet6_rth.c @@ -0,0 +1,192 @@ +/* Copyright (C) 2006 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@redhat.com>, 2006. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <string.h> +#include <netinet/in.h> +#include <netinet/ip6.h> + + +/* RFC 3542, 7.1 + + This function returns the number of bytes required to hold a + Routing header of the specified type containing the specified + number of segments (addresses). For an IPv6 Type 0 Routing header, + the number of segments must be between 0 and 127, inclusive. */ +socklen_t +inet6_rth_space (int type, int segments) +{ + switch (type) + { + case IPV6_RTHDR_TYPE_0: + if (segments < 0 || segments > 127) + return 0; + + return sizeof (struct ip6_rthdr0) + segments * sizeof (struct in6_addr); + } + + return 0; +} + + +/* RFC 3542, 7.2 + + This function initializes the buffer pointed to by BP to contain a + Routing header of the specified type and sets ip6r_len based on the + segments parameter. */ +void * +inet6_rth_init (void *bp, socklen_t bp_len, int type, int segments) +{ + struct ip6_rthdr *rthdr = (struct ip6_rthdr *) bp; + + switch (type) + { + case IPV6_RTHDR_TYPE_0: + /* Make sure the parameters are valid and the buffer is large enough. */ + if (segments < 0 || segments > 127) + break; + + socklen_t len = (sizeof (struct ip6_rthdr0) + + segments * sizeof (struct in6_addr)); + if (len > bp_len) + break; + + /* Some implementations seem to initialize the whole memory area. */ + memset (bp, '\0', len); + + /* Length in units of 8 octets. */ + rthdr->ip6r_len = segments * sizeof (struct in6_addr) / 8; + rthdr->ip6r_type = IPV6_RTHDR_TYPE_0; + return bp; + } + + return NULL; +} + + +/* RFC 3542, 7.3 + + This function adds the IPv6 address pointed to by addr to the end of + the Routing header being constructed. */ +int +inet6_rth_add (void *bp, const struct in6_addr *addr) +{ + struct ip6_rthdr *rthdr = (struct ip6_rthdr *) bp; + + switch (rthdr->ip6r_type) + { + struct ip6_rthdr0 *rthdr0; + case IPV6_RTHDR_TYPE_0: + rthdr0 = (struct ip6_rthdr0 *) rthdr; + + memcpy (&rthdr0->ip6r0_addr[rthdr0->ip6r0_segleft++], + addr, sizeof (struct in6_addr)); + + return 0; + } + + return -1; +} + + +/* RFC 3542, 7.4 + + This function takes a Routing header extension header (pointed to by + the first argument) and writes a new Routing header that sends + datagrams along the reverse of that route. The function reverses the + order of the addresses and sets the segleft member in the new Routing + header to the number of segments. */ +int +inet6_rth_reverse (const void *in, void *out) +{ + struct ip6_rthdr *in_rthdr = (struct ip6_rthdr *) in; + + switch (in_rthdr->ip6r_type) + { + struct ip6_rthdr0 *in_rthdr0; + struct ip6_rthdr0 *out_rthdr0; + case IPV6_RTHDR_TYPE_0: + in_rthdr0 = (struct ip6_rthdr0 *) in; + out_rthdr0 = (struct ip6_rthdr0 *) out; + + /* Copy header, not the addresses. The memory regions can overlap. */ + memmove (out_rthdr0, in_rthdr0, sizeof (struct ip6_rthdr0)); + + int total = in_rthdr0->ip6r0_segleft * 8 / sizeof (struct in6_addr); + for (int i = 0; i < total / 2; ++i) + { + /* Remember, IN_RTHDR0 and OUT_RTHDR0 might overlap. */ + struct in6_addr temp = in_rthdr0->ip6r0_addr[i]; + out_rthdr0->ip6r0_addr[i] = in_rthdr0->ip6r0_addr[total - 1 - i]; + out_rthdr0->ip6r0_addr[total - 1 - i] = temp; + } + if (total % 2 != 0 && in != out) + out_rthdr0->ip6r0_addr[total / 2] = in_rthdr0->ip6r0_addr[total / 2]; + + return 0; + } + + return -1; +} + + +/* RFC 3542, 7.5 + + This function returns the number of segments (addresses) contained in + the Routing header described by BP. */ +int +inet6_rth_segments (const void *bp) +{ + struct ip6_rthdr *rthdr = (struct ip6_rthdr *) bp; + + switch (rthdr->ip6r_type) + { + case IPV6_RTHDR_TYPE_0: + + return rthdr->ip6r_len * 8 / sizeof (struct in6_addr); + } + + return -1; +} + + +/* RFC 3542, 7.6 + + This function returns a pointer to the IPv6 address specified by + index (which must have a value between 0 and one less than the + value returned by 'inet6_rth_segments') in the Routing header + described by BP. */ +struct in6_addr * +inet6_rth_getaddr (const void *bp, int index) +{ + struct ip6_rthdr *rthdr = (struct ip6_rthdr *) bp; + + switch (rthdr->ip6r_type) + { + struct ip6_rthdr0 *rthdr0; + case IPV6_RTHDR_TYPE_0: + rthdr0 = (struct ip6_rthdr0 *) rthdr; + + if (index >= rthdr0->ip6r0_len * 8 / sizeof (struct in6_addr)) + break; + + return &rthdr0->ip6r0_addr[index]; + } + + return NULL; +} |