From 2b3fe33c07b17b6bbc6515f73aef5efac89fd542 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Mon, 18 Mar 2013 23:56:48 +0100 Subject: Implement hello and IHU sending and receiving --- src/babel.c | 230 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 230 insertions(+) create mode 100644 src/babel.c (limited to 'src/babel.c') diff --git a/src/babel.c b/src/babel.c new file mode 100644 index 0000000..39cd6c8 --- /dev/null +++ b/src/babel.c @@ -0,0 +1,230 @@ +/* + Copyright (c) 2013, Matthias Schiffer + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are met: + + 1. Redistributions of source code must retain the above copyright notice, + this list of conditions and the following disclaimer. + 2. Redistributions in binary form must reproduce the above copyright notice, + this list of conditions and the following disclaimer in the documentation + and/or other materials provided with the distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE + FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER + CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ + + +#include "babel.h" +#include "neigh.h" +#include "packet.h" +#include "tlv.h" +#include "tlv_types.h" + +#include + +#include + + +const char *gmrf_protocol_name = "babel"; +const char *gmrf_protocol_version = "experimental"; + + +static void add_ihus(gmrf_t *gmrf, gp_babel_packet_t *packet, size_t max_len, const gp_babel_iface_t *iface) { + const gp_babel_neigh_t *neigh; + + for (neigh = iface->neighbours; neigh; neigh = neigh->next) { + gp_babel_tlv_ihu_t *ihu = gp_babel_tlv_add(packet, GP_BABEL_PACKET_MAX, TLV_IHU, sizeof(gp_babel_tlv_ihu_t)+sizeof(gmrf_addr_t)); + if (!ihu) + return; + + ihu->ae = ADDR_ENC_GMRF; + ihu->reserved = 0; + ihu->rxcost = htons(gp_babel_neigh_get_rxcost(gmrf, neigh)); + ihu->interval = htons(GP_BABEL_IHU_INTERVAL); + memcpy(ihu->address, &neigh->addr, sizeof(gmrf_addr_t)); + } +} + +static void send_hellos(gmrf_t *gmrf, gmrf_context_t *ctx, void *arg) { + gmrf_schedule(gmrf, send_hellos, NULL, GP_BABEL_HELLO_INTERVAL*10); + + gmrf_logf(gmrf, LOG_DEBUG, "sending hellos..."); + + gp_babel_packet_t *packet = alloca(sizeof(gp_babel_packet_t)+GP_BABEL_PACKET_MAX); + + packet->version = htons(GP_BABEL_VERSION); + packet->len = 0; + + gp_babel_tlv_hello_t *hello = gp_babel_tlv_add(packet, GP_BABEL_PACKET_MAX, TLV_HELLO, sizeof(gp_babel_tlv_hello_t)); + if (!hello) + return; + + hello->reserved = 0; + hello->interval = htons(GP_BABEL_HELLO_INTERVAL); + + uint16_t len = packet->len; + + gp_babel_iface_t *iface; + for (iface = ctx->interfaces; iface; iface = iface->next) { + hello->seqno = htons(iface->seqno++); + + packet->len = len; + + add_ihus(gmrf, packet, GP_BABEL_PACKET_MAX, iface); + + gmrf_iface_send_bc(gmrf, iface->gmrf_iface, packet, sizeof(gp_babel_packet_t)+ntohs(packet->len)); + } +} + +gmrf_context_t* gmrf_protocol_init(gmrf_t *gmrf) { + gmrf_logf(gmrf, LOG_INFO, "initalizing..."); + + gmrf_schedule(gmrf, send_hellos, NULL, GP_BABEL_HELLO_INTERVAL*10); + + gmrf_context_t *ctx = calloc(1, sizeof(gmrf_context_t)); + gmrf_random_bytes(gmrf, &ctx->self, sizeof(gp_babel_node_id_t)); + + return ctx; +} + +void gmrf_protocol_add_iface(gmrf_t *gmrf, gmrf_context_t *ctx, gmrf_iface_t *iface) { + gmrf_logf(gmrf, LOG_INFO, "interface `%s' added.", gmrf_iface_get_name(gmrf, iface)); + + gp_babel_iface_t *b_iface = calloc(1, sizeof(gp_babel_iface_t)); + b_iface->gmrf_iface = iface; + + b_iface->next = ctx->interfaces; + ctx->interfaces = b_iface; +} + +typedef struct handle_tlv_arg { + gp_babel_iface_t *iface; + const gmrf_addr_t *source; + + gp_babel_node_id_t node_id; +} handle_tlv_arg_t; + +static inline gp_babel_neigh_t* get_tlv_neigh(handle_tlv_arg_t *arg) { + return gp_babel_neigh_get(arg->iface, arg->source); +} + +static void handle_tlv_hello(gmrf_t *gmrf, gmrf_context_t *ctx, const gp_babel_tlv_hello_t *tlv_hello, size_t len, handle_tlv_arg_t *arg) { + if (len < sizeof(gp_babel_tlv_hello_t)) { + gmrf_logf(gmrf, LOG_WARNING, "received short hello TLV."); + return; + } + + gmrf_logf(gmrf, LOG_DEBUG, "received hello with seqno %u.", ntohs(tlv_hello->seqno)); + + gp_babel_neigh_t *neigh = get_tlv_neigh(arg); + + uint16_t seqno = ntohs(tlv_hello->seqno); + + if (neigh->last_hello != gmrf_time_unspec) { + int timediff = (gmrf_now(gmrf) - neigh->last_hello)/10; + uint16_t seqexp = neigh->last_seqno + (timediff - neigh->hello_interval/2)/neigh->hello_interval; + + /* cast to int16_t to ensure correct handling of seqno wrapping */ + if (abs((int16_t)(seqno - seqexp)) > 16) { + gmrf_logf(gmrf, LOG_INFO, "neighbour was reset."); + neigh->hello_log = 0; + neigh->txcost = 0xffff; + } + else { + int16_t seqdiff = seqno - neigh->last_seqno; + if (seqdiff <= 0) { + gmrf_logf(gmrf, LOG_DEBUG, "seqno already seen, ignoring."); + return; + } + + neigh->hello_log <<= seqdiff; + } + } + else { + gmrf_logf(gmrf, LOG_DEBUG, "received hello from new neighbour."); + } + + neigh->hello_log |= 1; + neigh->hello_interval = ntohs(tlv_hello->interval); + neigh->last_seqno = seqno; + neigh->last_hello = gmrf_now(gmrf); + + if (neigh->hello_log == 1) /* new or reset neighbour */ + gp_babel_neigh_reset(arg->iface, neigh); + + gmrf_logf(gmrf, LOG_DEBUG, "accepted hello, log %04x, rxcost is %u, cost is %u now.", neigh->hello_log, gp_babel_neigh_get_rxcost(gmrf, neigh), gp_babel_neigh_get_cost(gmrf, neigh)); +} + +static void handle_tlv_ihu(gmrf_t *gmrf, gmrf_context_t *ctx, const gp_babel_tlv_ihu_t *tlv_ihu, size_t len, handle_tlv_arg_t *arg) { + if (len < sizeof(gp_babel_tlv_ihu_t)) { + gmrf_logf(gmrf, LOG_WARNING, "received short IHU TLV."); + return; + } + + if (tlv_ihu->ae == ADDR_ENC_GMRF) { + if (len < sizeof(gp_babel_tlv_ihu_t)+sizeof(gmrf_addr_t)) { + gmrf_logf(gmrf, LOG_WARNING, "received short IHU TLV."); + return; + } + + gmrf_addr_t iface_addr = gmrf_iface_get_addr(gmrf, arg->iface->gmrf_iface); + if (memcmp(tlv_ihu->address, &iface_addr, sizeof(gmrf_addr_t)) != 0) + return; + } + else if (tlv_ihu->ae != ADDR_ENC_UNSPEC) { + return; + } + + gp_babel_neigh_t *neigh = get_tlv_neigh(arg); + neigh->ihu_interval = ntohs(tlv_ihu->interval); + neigh->last_ihu = gmrf_now(gmrf); + neigh->txcost = ntohs(tlv_ihu->rxcost); + + gmrf_logf(gmrf, LOG_DEBUG, "accepted IHU, txcost is %u, cost is %u now.", gp_babel_neigh_get_txcost(gmrf, neigh), gp_babel_neigh_get_cost(gmrf, neigh)); +} + +static void handle_tlv(gmrf_t *gmrf, gmrf_context_t *ctx, gp_babel_tlv_type_t type, const void *data, size_t len, void *arg) { + handle_tlv_arg_t *tlv_arg = arg; + + switch (type) { + case TLV_HELLO: + handle_tlv_hello(gmrf, ctx, data, len, tlv_arg); + return; + + case TLV_IHU: + handle_tlv_ihu(gmrf, ctx, data, len, tlv_arg); + return; + + default: + gmrf_logf(gmrf, LOG_DEBUG, "received unknown TLV %u on %s.", type, gmrf_iface_get_name(gmrf, tlv_arg->iface->gmrf_iface)); + return; + } +} + +void gmrf_protocol_handle_packet(gmrf_t *gmrf, gmrf_context_t *ctx, gmrf_iface_t *iface, const gmrf_addr_t *source, const void *data, size_t len) { + const gp_babel_packet_t *packet = data; + + if (len < sizeof(gp_babel_packet_t) || len < sizeof(gp_babel_packet_t)+ntohs(packet->len)) { + gmrf_logf(gmrf, LOG_DEBUG, "received short packet."); + return; + } + + handle_tlv_arg_t arg = { .iface = gp_babel_get_iface(ctx, iface), .source = source }; + + if (!arg.iface) + return; + + if (!gp_babel_tlv_parse(gmrf, ctx, packet, handle_tlv, &arg)) { + gmrf_logf(gmrf, LOG_DEBUG, "received invalid packet."); + } +} -- cgit v1.2.3