tools/zep_dispatch: add simple ZEP dispatcher

dist/tools/Makefile

@@ -1,4 +1,4 @@
-HOST_TOOLS=ethos uhcpd sliptty
+HOST_TOOLS=ethos uhcpd sliptty zep_dispatch
 
 .PHONY: all $(HOST_TOOLS)
 

dist/tools/zep_dispatch/Makefile

@@ -0,0 +1,16 @@
+CFLAGS?=-g -O3 -Wall -Wextra
+
+BINARY := bin/zep_dispatch
+all: bin $(BINARY)
+
+bin:
+	mkdir bin
+
+RIOTBASE:=../../..
+RIOT_INCLUDE=$(RIOTBASE)/core/include
+SRCS:=$(wildcard *.c)
+$(BINARY): $(SRCS)
+	$(CC) $(CFLAGS) $(CFLAGS_EXTRA) -I$(RIOT_INCLUDE) $(SRCS) -o $@
+
+clean:
+	rm -f $(BINARY)

dist/tools/zep_dispatch/main.c

@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2020 Benjamin Valentin
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License v2. See the file LICENSE for more details.
+ */
+
+#ifndef ZEP_DISPATCH_PDU
+#define ZEP_DISPATCH_PDU    256
+#endif
+
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "list.h"
+#include "kernel_defines.h"
+
+typedef struct {
+    list_node_t node;
+    struct sockaddr_in6 addr;
+} zep_client_t;
+
+static void dispatch_loop(int sock)
+{
+    list_node_t head = { .next = NULL };
+
+    puts("entering loop…");
+    while (1) {
+        char addr_str[INET6_ADDRSTRLEN];
+        uint8_t buffer[ZEP_DISPATCH_PDU];
+        struct sockaddr_in6 src_addr;
+        socklen_t addr_len = sizeof(src_addr);
+
+        /* receive incoming packet */
+        ssize_t bytes_in = recvfrom(sock, buffer, sizeof(buffer), 0,
+                               (struct sockaddr*)&src_addr, &addr_len);
+
+        if (bytes_in <= 0 || addr_len != sizeof(src_addr)) {
+            continue;
+        }
+
+        /* send packet to all other clients */
+        bool known_node = false;
+        list_node_t *prev = &head;
+        for (list_node_t* n = head.next; n; n = n->next) {
+            struct sockaddr_in6 *addr = &container_of(n, zep_client_t, node)->addr;
+
+            /* don't echo packet back to sender */
+            if (memcmp(&src_addr, addr, addr_len) == 0) {
+                known_node = true;
+            /* remove client if sending fails */
+            } else if (sendto(sock, buffer, bytes_in, 0, (struct sockaddr*)addr, addr_len) < 0) {
+                inet_ntop(AF_INET6, &addr->sin6_addr, addr_str, INET6_ADDRSTRLEN);
+                printf("removing [%s]:%d\n", addr_str, ntohs(addr->sin6_port));
+                prev->next = n->next;
+                free(n);
+                continue;
+            }
+
+            prev = n;
+        }
+
+        /* if the client new, add it to the broadcast list */
+        if (!known_node) {
+            inet_ntop(AF_INET6, &src_addr.sin6_addr, addr_str, INET6_ADDRSTRLEN);
+            printf("adding [%s]:%d\n", addr_str, ntohs(src_addr.sin6_port));
+            zep_client_t *client = malloc(sizeof(zep_client_t));
+            memcpy(&client->addr, &src_addr, addr_len);
+            list_add(&head, &client->node);
+        }
+    }
+}
+
+int main(int argc, char **argv)
+{
+    if (argc < 3) {
+        fprintf(stderr, "usage: %s <address> <port>\n",
+                argv[0]);
+        exit(1);
+    }
+
+    struct addrinfo hint = {
+        .ai_family   = AF_INET6,
+        .ai_socktype = SOCK_DGRAM,
+        .ai_protocol = IPPROTO_UDP,
+        .ai_flags    = AI_NUMERICHOST,
+    };
+
+    struct addrinfo *server_addr;
+    int res = getaddrinfo(argv[1], argv[2],
+                          &hint, &server_addr);
+    if (res != 0) {
+        perror("getaddrinfo()");
+        exit(1);
+    }
+
+    int sock = socket(server_addr->ai_family, server_addr->ai_socktype,
+                      server_addr->ai_protocol);
+    if (sock < 0) {
+        perror("socket() failed");
+        exit(1);
+    }
+
+    if (bind(sock, server_addr->ai_addr, server_addr->ai_addrlen) < 0) {
+        perror("bind() failed");
+        exit(1);
+    }
+
+    freeaddrinfo(server_addr);
+
+    dispatch_loop(sock);
+
+    close(sock);
+
+    return 0;
+}

dist/tools/zep_dispatch/start_network.sh

@@ -0,0 +1,99 @@
+#!/usr/bin/env bash
+
+ZEP_DISPATCH_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+UHCPD="$(cd "${ZEP_DISPATCH_DIR}/../uhcpd/bin" && pwd -P)/uhcpd"
+DHCPD="$(cd "${ZEP_DISPATCH_DIR}/../dhcpv6-pd_ia/" && pwd -P)/dhcpv6-pd_ia.py"
+ZEP_DISPATCH="${ZEP_DISPATCH_DIR}/bin/zep_dispatch"
+
+TAP_GLB="fdea:dbee:f::1/64"
+
+NOSUDO="sudo -u ${SUDO_USER}"
+
+create_tap() {
+    ip tuntap add "${TAP}" mode tap user "${SUDO_USER}"
+    sysctl -w net.ipv6.conf."${TAP}".forwarding=1
+    sysctl -w net.ipv6.conf."${TAP}".accept_ra=0
+    ip link set "${TAP}" up
+    ip a a fe80::1/64 dev "${TAP}"
+    ip a a ${TAP_GLB} dev "${TAP}"
+    ip route add "${PREFIX}" via fe80::2 dev "${TAP}"
+}
+
+remove_tap() {
+    ip tuntap del "${TAP}" mode tap
+}
+
+cleanup() {
+    echo "Cleaning up..."
+    remove_tap
+    if [ -n "${UHCPD_PID}" ]; then
+        kill "${UHCPD_PID}"
+    fi
+    if [ -n "${ZEP_DISPATCH_PID}" ]; then
+        kill "${ZEP_DISPATCH_PID}"
+    fi
+    if [ -n "${DHCPD_PIDFILE}" ]; then
+        kill "$(cat "${DHCPD_PIDFILE}")"
+        rm "${DHCPD_PIDFILE}"
+    fi
+    trap "" INT QUIT TERM EXIT
+}
+
+start_uhcpd() {
+    ${UHCPD} "${TAP}" "${PREFIX}" > /dev/null &
+    UHCPD_PID=$!
+}
+
+start_dhcpd() {
+    DHCPD_PIDFILE=$(mktemp)
+    ${DHCPD} -d -p "${DHCPD_PIDFILE}" "${TAP}" "${PREFIX}" 2> /dev/null
+}
+
+start_zep_dispatch() {
+    ${ZEP_DISPATCH} :: "${ZEP_PORT_BASE}" > /dev/null &
+    ZEP_DISPATCH_PID=$!
+}
+
+if [ "$1" = "-d" ] || [ "$1" = "--use-dhcpv6" ]; then
+    USE_DHCPV6=1
+    shift 1
+else
+    USE_DHCPV6=0
+fi
+
+if [ "$1" = "-z" ] || [ "$1" = "--use-zep-dispatch" ]; then
+    USE_ZEP_DISPATCH=1
+    ZEP_PORT_BASE=$2
+    shift 2
+else
+    USE_ZEP_DISPATCH=0
+fi
+
+ELFFILE=$1
+PREFIX=$2
+shift 2
+
+# tap will be the last argument
+for TAP in "$@"; do :; done
+
+[[ -z "${ELFFILE}" || -z "${PREFIX}" || -z "${TAP}" ]] && {
+    echo "usage: $0 [-d|--use-dhcp] [-z|--use-zep <port>] " \
+         "<elffile> <prefix> [elf args]"
+    exit 1
+}
+
+trap "cleanup" INT QUIT TERM EXIT
+
+create_tap
+
+if [ ${USE_ZEP_DISPATCH} -eq 1 ]; then
+    start_zep_dispatch
+fi
+
+if [ ${USE_DHCPV6} -eq 1 ]; then
+    start_dhcpd
+else
+    start_uhcpd
+fi
+
+${NOSUDO} "${ELFFILE}" "${TAP}" "$@"