From ff0485ea8683816c1374bfc21f77a3623b10ed48 Mon Sep 17 00:00:00 2001 From: Eugene Crosser Date: Fri, 15 Mar 2019 16:17:16 +0100 Subject: [PATCH] construct multicast group using hash of channel Signed-off-by: Eugene Crosser --- src/psmb_socket.c | 34 ++++++++++++++++++++++++++++++---- 1 file changed, 30 insertions(+), 4 deletions(-) diff --git a/src/psmb_socket.c b/src/psmb_socket.c index 06b90a8..d18ad57 100644 --- a/src/psmb_socket.c +++ b/src/psmb_socket.c @@ -1,4 +1,5 @@ #include +#include #include #include #include @@ -8,6 +9,7 @@ #include #include "psmb_priv.h" +#include "hash64.h" static void dummy_log(void *log_priv, int priority, const char *format, ...) {} @@ -31,8 +33,8 @@ psmb_ctx_t *psmb_new_mm(void *(*malloc)(size_t size), .fd = -1, .malloc = malloc, .free = free, .realloc = realloc, .logf = dummy_log, - .prefix = (struct in6_addr){{{ 0xff, 0xff, 0x01, 0x05, - 0xb0, 0x55, 0xff, 0xe7, + .prefix = (struct in6_addr){{{ 0xff, 0x15, 'P', 'S', + 'M', 'B', '0', '1', 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }}}, .prefixlen = 64, @@ -83,6 +85,12 @@ psmb_result_t psmb_set_port(psmb_ctx_t *ctx, unsigned short port) psmb_result_t psmb_set_mgrp(psmb_ctx_t *ctx, struct in6_addr prefix, unsigned char prefixlen) { + if (prefixlen > 128) { + LOG(ctx, LOG_ERR, "psmb_set_mgrp() prefixlen %d is too big", + prefixlen); + errno = EINVAL; + return (psmb_result_t){PSMB_ERROR}; + } if (ctx->fd == -1) { ctx->prefix = prefix; ctx->prefixlen = prefixlen; @@ -145,19 +153,37 @@ psmb_result_t psmb_open(psmb_ctx_t *ctx) return (psmb_result_t){PSMB_OK}; } +static struct in6_addr multiaddr(struct in6_addr prefix, + unsigned char prefixlen, uint64_t suffix) +{ + struct in6_addr result = prefix; + unsigned char len = prefixlen > 64 ? prefixlen : 64; + uint64_t mask = len == 64 ? ~(uint64_t)0 : ((uint64_t)1 << len) - 1; + + *(uint64_t *)(&result.__in6_u.__u6_addr32[2]) &= ~mask; + *(uint64_t *)(&result.__in6_u.__u6_addr32[2]) |= (suffix & mask); + return result; +} + static psmb_result_t psmb_sub_unsub(psmb_ctx_t *ctx, char *channel, int option) { struct ipv6_mreq mreq = { 0 }; + char mgrp_str[INET6_ADDRSTRLEN+1]; if (ctx->fd == -1) { LOG(ctx, LOG_ERR, "subscribe: psmb is not open"); errno = EINVAL; return (psmb_result_t){PSMB_ERROR}; } - mreq.ipv6mr_multiaddr = ctx->prefix; /* use hash of the channel */ + mreq.ipv6mr_multiaddr = multiaddr(ctx->prefix, ctx->prefixlen, + hash64(channel, strlen(channel))); + (void)inet_ntop(AF_INET6, &mreq.ipv6mr_multiaddr, + mgrp_str, sizeof(mgrp_str)); + LOG(ctx, LOG_DEBUG, "using multiaddr %s for channel \"%s\"", + mgrp_str, channel); mreq.ipv6mr_interface = 0; /* how to use this??? */ if (setsockopt(ctx->fd, IPPROTO_IPV6, option, - (void *)&mreq, sizeof(mreq)) == -1) { + (void *)&mreq, sizeof(mreq)) == -1) { int sverr = errno; LOG(ctx, LOG_ERR, "add_membership(): %m"); errno = sverr; -- 2.39.2