From 000bd94557f07cea56b9d1d1b0c0328b8d17a507 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Tue, 17 Aug 2010 00:48:23 +0200 Subject: [PATCH] Add default gateway and DHCP handling (not fully working yet because of a kernel bug) --- dhcp.c | 57 +++++++++++++++++++++- main.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++++------- relayd.h | 19 ++++++-- route.c | 53 +++++++++++++++++---- 4 files changed, 239 insertions(+), 33 deletions(-) diff --git a/dhcp.c b/dhcp.c index a144346..9dbea28 100644 --- a/dhcp.c +++ b/dhcp.c @@ -29,6 +29,19 @@ struct ip_packet { struct iphdr iph; } __packed; + +enum { + DHCP_OPTION_ROUTER = 0x03, + DHCP_OPTION_ROUTES = 0x79, + DHCP_OPTION_END = 0xff, +}; + +struct dhcp_option { + uint8_t code; + uint8_t len; + uint8_t data[]; +}; + struct dhcp_header { uint8_t op, htype, hlen, hops; uint32_t xit; @@ -37,6 +50,8 @@ struct dhcp_header { unsigned char chaddr[16]; unsigned char sname[64]; unsigned char file[128]; + uint32_t cookie; + uint8_t option_data[]; } __packed; static uint16_t @@ -65,11 +80,46 @@ chksum(uint16_t sum, const uint8_t *data, uint16_t len) return sum; } +static void +parse_dhcp_options(struct relayd_host *host, struct dhcp_header *dhcp, int len) +{ + uint8_t *end = (uint8_t *) dhcp + len; + struct dhcp_option *opt = (void *)dhcp->option_data; + static const uint8_t dest[4] = { 0, 0, 0, 0 }; + + while((uint8_t *) opt < end) { + if ((uint8_t *) opt + opt->len > end) + break; + + opt = (void *) &opt->data[opt->len]; + switch(opt->code) { + case DHCP_OPTION_ROUTER: + DPRINTF(2, "Found a DHCP router option, len=%d\n", opt->len); + if (!memcmp(opt->data, host->ipaddr, 4)) + relayd_add_host_route(host, dest, 0); + else + relayd_add_pending_route(opt->data, dest, 0, 10000); + break; + case DHCP_OPTION_ROUTES: + DPRINTF(2, "Found a DHCP static routes option, len=%d\n", opt->len); + break; + case DHCP_OPTION_END: + opt = (void *) end; + continue; + default: + DPRINTF(3, "Skipping unknown DHCP option %02x\n", opt->code); + continue; + } + + } +} + bool relayd_handle_dhcp_packet(struct relayd_interface *rif, void *data, int len, bool forward) { struct ip_packet *pkt = data; struct udphdr *udp; struct dhcp_header *dhcp; + struct relayd_host *host; int udplen; uint16_t sum; @@ -98,8 +148,11 @@ bool relayd_handle_dhcp_packet(struct relayd_interface *rif, void *data, int len if (!forward) return true; - if (dhcp->op == 2) - relayd_refresh_host(rif, pkt->eth.ether_shost, (void *) &pkt->iph.saddr); + if (dhcp->op == 2) { + host = relayd_refresh_host(rif, pkt->eth.ether_shost, (void *) &pkt->iph.saddr); + if (host) + parse_dhcp_options(host, dhcp, udplen - sizeof(struct udphdr)); + } DPRINTF(2, "%s: handling DHCP %s\n", rif->ifname, (dhcp->op == 1 ? "request" : "response")); diff --git a/main.c b/main.c index 62d7c2b..ef669fa 100644 --- a/main.c +++ b/main.c @@ -31,6 +31,7 @@ #include "relayd.h" +static LIST_HEAD(pending_routes); LIST_HEAD(interfaces); int debug; @@ -39,6 +40,12 @@ static int inet_sock; static int forward_bcast; static int forward_dhcp; +struct relayd_pending_route { + struct relayd_route rt; + struct uloop_timeout timeout; + uint8_t gateway[4]; +}; + static struct relayd_host *find_host_by_ipaddr(struct relayd_interface *rif, const uint8_t *ipaddr) { struct relayd_host *host; @@ -81,20 +88,55 @@ static void add_arp(struct relayd_host *host) ioctl(inet_sock, SIOCSARP, &arp); } +static void timeout_host_route(struct uloop_timeout *timeout) +{ + struct relayd_pending_route *rt; + + rt = container_of(timeout, struct relayd_pending_route, timeout); + list_del(&rt->rt.list); + free(rt); +} + +void relayd_add_host_route(struct relayd_host *host, const uint8_t *dest, uint8_t mask) +{ + struct relayd_route *rt; + + list_for_each_entry(rt, &host->routes, list) { + if (!memcmp(rt->dest, dest, sizeof(rt->dest)) && rt->mask == mask) + return; + } + + rt = calloc(1, sizeof(*rt)); + if (!rt) + return; + + list_add(&rt->list, &host->routes); + memcpy(rt->dest, dest, sizeof(rt->dest)); + rt->mask = mask; + relayd_add_route(host, rt); +} + static void del_host(struct relayd_host *host) { + struct relayd_route *route, *tmp; + DPRINTF(1, "%s: deleting host "IP_FMT" ("MAC_FMT")\n", host->rif->ifname, IP_BUF(host->ipaddr), MAC_BUF(host->lladdr)); + list_for_each_entry_safe(route, tmp, &host->routes, list) { + relayd_del_route(host, route); + list_del(&route->list); + free(route); + } if (host->rif->managed) - relayd_del_route(host); + relayd_del_route(host, NULL); uloop_timeout_cancel(&host->timeout); list_del(&host->list); free(host); } static void fill_arp_request(struct arp_packet *pkt, struct relayd_interface *rif, - uint8_t spa[4], uint8_t tpa[4]) + const uint8_t spa[4], const uint8_t tpa[4]) { memset(pkt, 0, sizeof(*pkt)); @@ -111,12 +153,11 @@ static void fill_arp_request(struct arp_packet *pkt, struct relayd_interface *ri pkt->arp.arp_pln = 4; } -static void send_arp_request(struct relayd_host *host) +static void send_arp_request(struct relayd_interface *rif, const uint8_t *ipaddr) { - struct relayd_interface *rif = host->rif; struct arp_packet pkt; - fill_arp_request(&pkt, host->rif, host->rif->src_ip, host->ipaddr); + fill_arp_request(&pkt, rif, rif->src_ip, ipaddr); pkt.arp.arp_op = htons(ARPOP_REQUEST); memcpy(pkt.arp.arp_spa, rif->src_ip, ETH_ALEN); @@ -131,6 +172,36 @@ static void send_arp_request(struct relayd_host *host) (struct sockaddr *) &rif->sll, sizeof(rif->sll)); } +void relayd_add_pending_route(const uint8_t *gateway, const uint8_t *dest, uint8_t mask, int timeout) +{ + struct relayd_pending_route *rt; + struct relayd_interface *rif; + struct relayd_host *host; + + host = find_host_by_ipaddr(NULL, gateway); + if (host) { + relayd_add_host_route(host, dest, mask); + return; + } + + rt = calloc(1, sizeof(*rt)); + if (!rt) + return; + + memcpy(rt->gateway, gateway, sizeof(rt->gateway)); + memcpy(rt->rt.dest, dest, sizeof(rt->rt.dest)); + rt->rt.mask = mask; + list_add(&rt->rt.list, &pending_routes); + if (timeout <= 0) + return; + + rt->timeout.cb = timeout_host_route; + uloop_timeout_set(&rt->timeout, 10000); + list_for_each_entry(rif, &interfaces, list) { + send_arp_request(rif, gateway); + } +} + static void send_arp_reply(struct relayd_interface *rif, uint8_t spa[4], uint8_t tha[ETH_ALEN], uint8_t tpa[4]) { @@ -162,7 +233,7 @@ static void host_entry_timeout(struct uloop_timeout *timeout) * giving up on it. */ if (host->rif->managed && host->cleanup_pending < 2) { - send_arp_request(host); + send_arp_request(host->rif, host->ipaddr); host->cleanup_pending++; uloop_timeout_set(&host->timeout, 1000); return; @@ -173,11 +244,13 @@ static void host_entry_timeout(struct uloop_timeout *timeout) static struct relayd_host *add_host(struct relayd_interface *rif, const uint8_t *lladdr, const uint8_t *ipaddr) { struct relayd_host *host; + struct relayd_pending_route *route, *rtmp; DPRINTF(1, "%s: adding host "IP_FMT" ("MAC_FMT")\n", rif->ifname, IP_BUF(ipaddr), MAC_BUF(lladdr)); host = calloc(1, sizeof(*host)); + INIT_LIST_HEAD(&host->routes); host->rif = rif; memcpy(host->ipaddr, ipaddr, sizeof(host->ipaddr)); memcpy(host->lladdr, lladdr, sizeof(host->lladdr)); @@ -187,7 +260,20 @@ static struct relayd_host *add_host(struct relayd_interface *rif, const uint8_t add_arp(host); if (rif->managed) - relayd_add_route(host); + relayd_add_route(host, NULL); + + list_for_each_entry_safe(route, rtmp, &pending_routes, rt.list) { + if (memcmp(route->gateway, ipaddr, 4) != 0) + continue; + + relayd_add_host_route(host, route->rt.dest, route->rt.mask); + if (!route->timeout.pending) + continue; + + uloop_timeout_cancel(&route->timeout); + list_del(&route->rt.list); + free(route); + } return host; } @@ -207,8 +293,10 @@ struct relayd_host *relayd_refresh_host(struct relayd_interface *rif, const uint * If the old entry is behind a managed interface, it will be pinged * before we expire it */ - if (host && !host->cleanup_pending) + if (host && !host->cleanup_pending) { uloop_timeout_set(&host->timeout, 1); + return NULL; + } host = add_host(rif, lladdr, ipaddr); } else { @@ -281,7 +369,8 @@ static void recv_arp_reply(struct relayd_interface *rif, struct arp_packet *pkt) MAC_BUF(pkt->eth.ether_shost), IP_BUF(pkt->arp.arp_tpa)); - relayd_refresh_host(rif, pkt->arp.arp_sha, pkt->arp.arp_spa); + if (memcmp(pkt->arp.arp_sha, rif->sll.sll_addr, ETH_ALEN) != 0) + relayd_refresh_host(rif, pkt->arp.arp_sha, pkt->arp.arp_spa); if (!memcmp(pkt->arp.arp_tpa, rif->src_ip, 4)) return; @@ -459,6 +548,16 @@ static int init_interface(struct relayd_interface *rif) return 0; } +static void ping_static_routes(void) +{ + struct relayd_pending_route *rt; + struct relayd_interface *rif; + + list_for_each_entry(rt, &pending_routes, rt.list) + list_for_each_entry(rif, &interfaces, list) + send_arp_request(rif, rt->gateway); +} + static int init_interfaces(void) { struct relayd_interface *rif; @@ -496,24 +595,23 @@ static void free_interfaces(void) } } -static int alloc_interface(const char *ifname, bool managed) +static struct relayd_interface *alloc_interface(const char *ifname, bool managed) { struct relayd_interface *rif; if (strlen(ifname) >= IFNAMSIZ) - return -1; + return NULL; rif = calloc(1, sizeof(*rif)); if (!rif) - return -1; + return NULL; - INIT_LIST_HEAD(&rif->list); INIT_LIST_HEAD(&rif->hosts); strcpy(rif->ifname, ifname); list_add(&rif->list, &interfaces); rif->managed = managed; - return 0; + return rif; } static void die(int signo) @@ -536,6 +634,7 @@ static int usage(const char *progname) " -i Add an interface for relaying\n" " -I Same as -i, except with ARP cache and host route management\n" " You need to specify at least two interfaces\n" + " -G Set a gateway IP for clients\n" " -t Host entry expiry timeout\n" " -T Set routing table number for automatically added routes\n" " -B Enable broadcast forwarding\n" @@ -547,6 +646,8 @@ static int usage(const char *progname) int main(int argc, char **argv) { + struct relayd_interface *rif = NULL; + struct in_addr addr; bool managed; int ifnum = 0; int ch; @@ -562,14 +663,15 @@ int main(int argc, char **argv) forward_bcast = 0; uloop_init(); - while ((ch = getopt(argc, argv, "I:i:t:BDdT:")) != -1) { + while ((ch = getopt(argc, argv, "I:i:t:BDdT:G:")) != -1) { switch(ch) { case 'I': managed = true; /* fall through */ case 'i': ifnum++; - if (alloc_interface(optarg, managed) < 0) + rif = alloc_interface(optarg, managed); + if (!rif) return 1; managed = false; @@ -593,6 +695,13 @@ int main(int argc, char **argv) if (route_table <= 0) return usage(argv[0]); break; + case 'G': + if (!inet_aton(optarg, &addr)) { + fprintf(stderr, "Address '%s' not found\n", optarg); + return 1; + } + relayd_add_pending_route((uint8_t *) &addr.s_addr, (const uint8_t *) "\x00\x00\x00\x00", 0, 0); + break; case '?': default: return usage(argv[0]); @@ -621,6 +730,8 @@ int main(int argc, char **argv) if (init_interfaces() < 0) return 1; + ping_static_routes(); + uloop_run(); uloop_done(); diff --git a/relayd.h b/relayd.h index 3ae4edc..e21ca08 100644 --- a/relayd.h +++ b/relayd.h @@ -73,6 +73,7 @@ struct relayd_interface { struct relayd_host { struct list_head list; + struct list_head routes; struct relayd_interface *rif; uint8_t lladdr[ETH_ALEN]; uint8_t ipaddr[4]; @@ -80,6 +81,12 @@ struct relayd_host { int cleanup_pending; }; +struct relayd_route { + struct list_head list; + uint8_t dest[4]; + uint8_t mask; +}; + struct arp_packet { struct ether_header eth; struct ether_arp arp; @@ -94,16 +101,16 @@ extern struct list_head interfaces; extern int debug; extern int route_table; -void rtnl_route_set(struct relayd_host *host, bool add); +void rtnl_route_set(struct relayd_host *host, struct relayd_route *route, bool add); -static inline void relayd_add_route(struct relayd_host *host) +static inline void relayd_add_route(struct relayd_host *host, struct relayd_route *route) { - rtnl_route_set(host, true); + rtnl_route_set(host, route, true); } -static inline void relayd_del_route(struct relayd_host *host) +static inline void relayd_del_route(struct relayd_host *host, struct relayd_route *route) { - rtnl_route_set(host, false); + rtnl_route_set(host, route, false); } void relayd_add_interface_routes(struct relayd_interface *rif); @@ -115,6 +122,8 @@ void relayd_rtnl_done(void); struct relayd_host *relayd_refresh_host(struct relayd_interface *rif, const uint8_t *lladdr, const uint8_t *ipaddr); +void relayd_add_host_route(struct relayd_host *host, const uint8_t *ipaddr, uint8_t mask); +void relayd_add_pending_route(const uint8_t *gateway, const uint8_t *dest, uint8_t mask, int timeout); void relayd_forward_bcast_packet(struct relayd_interface *from_rif, void *packet, int len); bool relayd_handle_dhcp_packet(struct relayd_interface *rif, void *data, int len, bool forward); diff --git a/route.c b/route.c index c41100d..25f949e 100644 --- a/route.c +++ b/route.c @@ -42,7 +42,9 @@ static void rtnl_flush(void) close(fd); } -static void rtnl_route_request(struct relayd_interface *rif, struct relayd_host *host, bool add) +static void +rtnl_route_request(struct relayd_interface *rif, struct relayd_host *host, + struct relayd_route *route, bool add) { static struct { struct nlmsghdr nl; @@ -59,10 +61,11 @@ static void rtnl_route_request(struct relayd_interface *rif, struct relayd_host struct rtattr rta; int ifindex; } __packed dev; + struct { + struct rtattr rta; + uint8_t ipaddr[4]; + } __packed gw; } __packed req = { - .nl = { - .nlmsg_len = sizeof(req), - }, .rt = { .rtm_family = AF_INET, .rtm_dst_len = 32, @@ -73,16 +76,19 @@ static void rtnl_route_request(struct relayd_interface *rif, struct relayd_host .rta_len = sizeof(req.table), }, .dst.rta = { - .rta_type = RTA_DST, .rta_len = sizeof(req.dst), }, .dev.rta = { .rta_type = RTA_OIF, .rta_len = sizeof(req.dev), }, + .gw.rta = { + .rta_type = RTA_GATEWAY, + .rta_len = sizeof(req.gw), + }, }; + int pktlen = sizeof(req); - memcpy(req.dst.ipaddr, host->ipaddr, sizeof(req.dst.ipaddr)); req.dev.ifindex = host->rif->sll.sll_ifindex; req.table.table = rif->rt_table; @@ -92,14 +98,40 @@ static void rtnl_route_request(struct relayd_interface *rif, struct relayd_host req.nl.nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE; req.rt.rtm_protocol = RTPROT_BOOT; - req.rt.rtm_scope = RT_SCOPE_LINK; + if (route) { + req.rt.rtm_scope = RT_SCOPE_UNIVERSE; + } else { + req.rt.rtm_scope = RT_SCOPE_LINK; + } req.rt.rtm_type = RTN_UNICAST; } else { req.nl.nlmsg_type = RTM_DELROUTE; req.rt.rtm_scope = RT_SCOPE_NOWHERE; } - send(rtnl_sock.fd, &req, sizeof(req), 0); + req.dst.rta.rta_type = RTA_DST; + if (route) { + DPRINTF(2, "%s: add route to "IP_FMT"/%d via "IP_FMT"\n", + host->rif->ifname, IP_BUF(route->dest), route->mask, IP_BUF(host->ipaddr)); + if (!route->mask) { + /* No DST -> reuse the DST attribute as the gateway attribute */ + memcpy(req.dst.ipaddr, host->ipaddr, sizeof(req.dst.ipaddr)); + req.dst.rta.rta_type = RTA_GATEWAY; + pktlen -= sizeof(req.gw); + req.rt.rtm_dst_len = 0; + } else { + memcpy(req.gw.ipaddr, host->ipaddr, sizeof(req.gw.ipaddr)); + memcpy(req.dst.ipaddr, route->dest, sizeof(req.dst.ipaddr)); + req.rt.rtm_dst_len = route->mask; + } + } else { + pktlen -= sizeof(req.gw); + req.rt.rtm_dst_len = 32; + memcpy(req.dst.ipaddr, host->ipaddr, sizeof(req.dst.ipaddr)); + } + + req.nl.nlmsg_len = pktlen; + send(rtnl_sock.fd, &req, pktlen, 0); rtnl_flush(); } @@ -155,7 +187,8 @@ static void rtnl_rule_request(struct relayd_interface *rif, bool add) rtnl_flush(); } -void rtnl_route_set(struct relayd_host *host, bool add) +void +rtnl_route_set(struct relayd_host *host, struct relayd_route *route, bool add) { struct relayd_interface *rif; @@ -163,7 +196,7 @@ void rtnl_route_set(struct relayd_host *host, bool add) if (rif == host->rif) continue; - rtnl_route_request(rif, host, add); + rtnl_route_request(rif, host, route, add); } } -- 2.30.2