X-Git-Url: http://git.archive.openwrt.org/?p=project%2Fodhcpd.git;a=blobdiff_plain;f=src%2Fdhcpv4.c;h=0f613b2206a985fcfae634b1e2acf6721273706b;hp=b4b072041c93ec43ae763350e8a457a7da91d765;hb=a278f7fbafe043164204502d1c04632af8cb5dea;hpb=7ccb1f94756db1c737d978f530276a3ac266f7e8;ds=sidebyside diff --git a/src/dhcpv4.c b/src/dhcpv4.c index b4b0720..0f613b2 100644 --- a/src/dhcpv4.c +++ b/src/dhcpv4.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -33,22 +34,45 @@ static void handle_dhcpv4(void *addr, void *data, size_t len, - struct interface *iface); + struct interface *iface, void *dest_addr); static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface, enum dhcpv4_msg msg, const uint8_t *mac, struct in_addr reqaddr, const char *hostname); - // Create socket and register events int init_dhcpv4(void) { return 0; } +char *dhcpv4_msg_to_string(uint8_t reqmsg) +{ + switch (reqmsg) { + case (DHCPV4_MSG_DISCOVER): + return "DHCPV4_MSG_DISCOVER"; + case (DHCPV4_MSG_OFFER): + return "DHCPV4_MSG_OFFER"; + case (DHCPV4_MSG_REQUEST): + return "DHCPV4_MSG_REQUEST"; + case (DHCPV4_MSG_DECLINE): + return "DHCPV4_MSG_DECLINE"; + case (DHCPV4_MSG_ACK): + return "DHCPV4_MSG_ACK"; + case (DHCPV4_MSG_NAK): + return "DHCPV4_MSG_NAK"; + case (DHCPV4_MSG_RELEASE): + return "DHCPV4_MSG_RELEASE"; + case (DHCPV4_MSG_INFORM): + return "DHCPV4_MSG_INFORM"; + default: + return "UNKNOWN"; + } +} int setup_dhcpv4_interface(struct interface *iface, bool enable) { if (iface->dhcpv4_event.uloop.fd > 0) { + uloop_fd_delete(&iface->dhcpv4_event.uloop); close(iface->dhcpv4_event.uloop.fd); iface->dhcpv4_event.uloop.fd = -1; } @@ -58,6 +82,11 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable) INIT_LIST_HEAD(&iface->dhcpv4_assignments); int sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP); + if (sock < 0) { + syslog(LOG_ERR, "Failed to create DHCPv4 server socket: %s", + strerror(errno)); + return -1; + } // Basic IPv6 configuration int val = 1; @@ -90,40 +119,39 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable) } // Create a range if not specified - struct ifreq ifreq; - strncpy(ifreq.ifr_name, iface->ifname, sizeof(ifreq.ifr_name)); - - struct sockaddr_in *saddr = (struct sockaddr_in*)&ifreq.ifr_addr; - struct sockaddr_in *smask = (struct sockaddr_in*)&ifreq.ifr_netmask; if (!(iface->dhcpv4_start.s_addr & htonl(0xffff0000)) && - !(iface->dhcpv4_end.s_addr & htonl(0xffff0000)) && - !ioctl(sock, SIOCGIFADDR, &ifreq)) { - struct in_addr addr = saddr->sin_addr; + !(iface->dhcpv4_end.s_addr & htonl(0xffff0000))) { + struct in_addr addr = ubus_get_address4(iface->ifname); - ioctl(sock, SIOCGIFNETMASK, &ifreq); - struct in_addr mask = smask->sin_addr; + struct in_addr mask = ubus_get_mask4(iface->ifname); uint32_t start = ntohl(iface->dhcpv4_start.s_addr); uint32_t end = ntohl(iface->dhcpv4_end.s_addr); if (start && end && start < end && start > ntohl(addr.s_addr & ~mask.s_addr) && - (start & ntohl(mask.s_addr)) == start && - (end & ntohl(mask.s_addr)) == end) { + (start & ntohl(~mask.s_addr)) == start && + (end & ntohl(~mask.s_addr)) == end) { iface->dhcpv4_start.s_addr = htonl(start) | (addr.s_addr & mask.s_addr); iface->dhcpv4_end.s_addr = htonl(end) | (addr.s_addr & mask.s_addr); - } else if (ntohl(mask.s_addr) <= 0xffffffc0) { + } else if (ntohl(mask.s_addr) <= 0xfffffff0) { start = addr.s_addr & mask.s_addr; end = addr.s_addr & mask.s_addr; if (ntohl(mask.s_addr) <= 0xffffff00) { iface->dhcpv4_start.s_addr = start | htonl(100); iface->dhcpv4_end.s_addr = end | htonl(250); - } else { + } else if (ntohl(mask.s_addr) <= 0xffffffc0) { + iface->dhcpv4_start.s_addr = start | htonl(10); + iface->dhcpv4_end.s_addr = end | htonl(60); + } else if (ntohl(mask.s_addr) <= 0xffffffe0) { iface->dhcpv4_start.s_addr = start | htonl(10); - iface->dhcpv4_end.s_addr = end | htonl(59); + iface->dhcpv4_end.s_addr = end | htonl(30); + } else { + iface->dhcpv4_start.s_addr = start | htonl(3); + iface->dhcpv4_end.s_addr = end | htonl(12); } } @@ -136,21 +164,30 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable) // Construct entry size_t hostlen = strlen(lease->hostname) + 1; struct dhcpv4_assignment *a = calloc(1, sizeof(*a) + hostlen); - + if (!a) { + syslog(LOG_ERR, "Calloc failed for static lease on interface %s", + iface->ifname); + return -1; + } a->addr = ntohl(lease->ipaddr.s_addr); memcpy(a->hwaddr, lease->mac.ether_addr_octet, sizeof(a->hwaddr)); memcpy(a->hostname, lease->hostname, hostlen); + a->valid_until = LONG_MAX; // Assign to all interfaces struct dhcpv4_assignment *c; list_for_each_entry(c, &iface->dhcpv4_assignments, head) { if (c->addr > a->addr) { list_add_tail(&a->head, &c->head); + break; } else if (c->addr == a->addr) { // Already an assignment with that number break; } } + if (&c->head == &iface->dhcpv4_assignments) { + list_add(&a->head, &iface->dhcpv4_assignments); + } if (!a->head.next) free(a); @@ -160,7 +197,7 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable) struct dhcpv4_assignment *a, *n; list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) { if ((htonl(a->addr) & smask->sin_addr.s_addr) != - (saddr->sin_addr.s_addr & smask->sin_addr.s_addr)) { + (iface->dhcpv4_start.s_addr & smask->sin_addr.s_addr)) { list_del(&a->head); free(a); } @@ -178,7 +215,6 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable) struct dhcpv4_assignment *a = list_first_entry(&iface->dhcpv4_assignments, struct dhcpv4_assignment, head); list_del(&a->head); - free(a->hostname); free(a); } @@ -204,7 +240,7 @@ static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie, // Simple DHCPv6-server for information requests static void handle_dhcpv4(void *addr, void *data, size_t len, - struct interface *iface) + struct interface *iface, _unused void *dest_addr) { if (!iface->dhcpv4) return; @@ -284,6 +320,13 @@ static void handle_dhcpv4(void *addr, void *data, size_t len, } else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) { if (memcmp(opt->data, &ifaddr.sin_addr, 4)) return; + } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) { + uint8_t *c = opt->data, *cend = &opt->data[opt->len]; + for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) { + size_t elen = strlen(iface->filter_class); + if (*c == elen && !memcmp(&c[1], iface->filter_class, elen)) + return; // Ignore from homenet + } } } @@ -303,8 +346,26 @@ static void handle_dhcpv4(void *addr, void *data, size_t len, return; } else if (reqmsg == DHCPV4_MSG_DISCOVER) { msg = DHCPV4_MSG_OFFER; + } else if (reqmsg == DHCPV4_MSG_REQUEST && reqaddr.s_addr && + reqaddr.s_addr != htonl(lease->addr)) { + msg = DHCPV4_MSG_NAK; + /* + * DHCP client requested an IP which we can't offer to him. Probably the + * client changed the network. The reply type is set to DHCPV4_MSG_NAK, + * because the client should not use that IP. + * + * For modern devices we build an answer that includes a valid IP, like + * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to + * perform additional DHCP round trips. + * + */ } + syslog(LOG_WARNING, "received %s from %x:%x:%x:%x:%x:%x", + dhcpv4_msg_to_string(reqmsg), + req->chaddr[0],req->chaddr[1],req->chaddr[2], + req->chaddr[3],req->chaddr[4],req->chaddr[5]); + if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE) return; @@ -340,18 +401,23 @@ static void handle_dhcpv4(void *addr, void *data, size_t len, dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu); } - if (iface->search) { - char b[256]; - if (dn_expand(iface->search, iface->search + iface->search_len, - iface->search, b, sizeof(b)) > 0) - dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DOMAIN, strlen(b), b); + if (iface->search && iface->search_len <= 255) { + dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN, + iface->search_len, iface->search); } else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) { - dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DOMAIN, - strlen(_res.dnsrch[0]), _res.dnsrch[0]); + uint8_t search_buf[256]; + int len = dn_comp(_res.dnsrch[0], search_buf, + sizeof(search_buf), NULL, NULL); + if (len > 0) + dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN, + len, search_buf); } - dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &ifaddr.sin_addr); - + if (iface->dhcpv4_router_cnt == 0) + dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &ifaddr.sin_addr); + else + dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, + 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router); if (iface->dhcpv4_dns_cnt == 0) @@ -365,16 +431,36 @@ static void handle_dhcpv4(void *addr, void *data, size_t len, struct sockaddr_in dest = *((struct sockaddr_in*)addr); if (req->giaddr.s_addr) { + /* + * relay agent is configured, send reply to the agent + */ dest.sin_addr = req->giaddr; dest.sin_port = htons(DHCPV4_SERVER_PORT); } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) { + /* + * client has existing configuration (ciaddr is set) AND this address is + * not the address it used for the dhcp message + */ dest.sin_addr = req->ciaddr; dest.sin_port = htons(DHCPV4_CLIENT_PORT); } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) || - req->hlen != reply.hlen) { + req->hlen != reply.hlen || !reply.yiaddr.s_addr) { + /* + * client requests a broadcast reply OR we can't offer an IP + */ + dest.sin_addr.s_addr = INADDR_BROADCAST; + dest.sin_port = htons(DHCPV4_CLIENT_PORT); + } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) { + /* + * client has no previous configuration -> no IP, so we need to reply + * with a broadcast packet + */ dest.sin_addr.s_addr = INADDR_BROADCAST; dest.sin_port = htons(DHCPV4_CLIENT_PORT); } else { + /* + * send reply to the newly (in this proccess) allocated IP + */ dest.sin_addr = reply.yiaddr; dest.sin_port = htons(DHCPV4_CLIENT_PORT); @@ -385,54 +471,97 @@ static void handle_dhcpv4(void *addr, void *data, size_t len, ioctl(sock, SIOCSARP, &arp); } + if (dest.sin_addr.s_addr == INADDR_BROADCAST) { + /* + * reply goes to IP broadcast -> MAC broadcast + */ + syslog(LOG_WARNING, "sending %s to ff:ff:ff:ff:ff:ff - %s", + dhcpv4_msg_to_string(msg), + inet_ntoa(dest.sin_addr)); + } else { + /* + * reply is send directly to IP, + * MAC is assumed to be the same as the request + */ + syslog(LOG_WARNING, "sending %s to %x:%x:%x:%x:%x:%x - %s", + dhcpv4_msg_to_string(msg), + req->chaddr[0],req->chaddr[1],req->chaddr[2], + req->chaddr[3],req->chaddr[4],req->chaddr[5], + inet_ntoa(dest.sin_addr)); + } + sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)); } +static bool dhcpv4_test(struct interface *iface, uint32_t try) +{ + struct dhcpv4_assignment *c; + list_for_each_entry(c, &iface->dhcpv4_assignments, head) { + if (c->addr == try) { + return false; + } + } + return true; +} static bool dhcpv4_assign(struct interface *iface, struct dhcpv4_assignment *assign, uint32_t raddr) { - const unsigned tries = 10; uint32_t start = ntohl(iface->dhcpv4_start.s_addr); uint32_t end = ntohl(iface->dhcpv4_end.s_addr); uint32_t count = end - start + 1; - // Seed RNG with checksum of DUID + // try to assign the IP the client asked for + if (start <= raddr && raddr <= end && dhcpv4_test(iface, raddr)) { + assign->addr = raddr; + list_add(&assign->head, &iface->dhcpv4_assignments); + syslog(LOG_DEBUG, "assigning the IP the client asked for: %u.%u.%u.%u", + (assign->addr & 0xff000000) >> 24, + (assign->addr & 0x00ff0000) >> 16, + (assign->addr & 0x0000ff00) >> 8, + (assign->addr & 0x000000ff)); + return true; + } + + // Seed RNG with checksum of hwaddress uint32_t seed = 0; - for (size_t i = 0; i < sizeof(assign->hwaddr); ++i) - seed += assign->hwaddr[i]; + for (size_t i = 0; i < sizeof(assign->hwaddr); ++i) { + // Knuth's multiplicative method + uint8_t o = assign->hwaddr[i]; + seed += (o*2654435761) % UINT32_MAX; + } srand(seed); - // Try to assign up to 100x - for (unsigned i = 0; i < tries; ++i) { - uint32_t try = (((uint32_t)rand()) % count) + start; - if (i == 0 && raddr >= start && raddr <= end) - try = raddr; - else if (i == tries - 1) - try = start; + uint32_t try = (((uint32_t)rand()) % count) + start; + + if (list_empty(&iface->dhcpv4_assignments)) { + assign->addr = try; + list_add(&assign->head, &iface->dhcpv4_assignments); + syslog(LOG_DEBUG, "assigning mapped IP (empty list): %u.%u.%u.%u", + (assign->addr & 0xff000000) >> 24, + (assign->addr & 0x00ff0000) >> 16, + (assign->addr & 0x0000ff00) >> 8, + (assign->addr & 0x000000ff)); + return true; + } - if (list_empty(&iface->dhcpv4_assignments)) { + for (uint32_t i = 0; i < count; ++i) { + if (dhcpv4_test(iface, try)) { + /* test was successful: IP address is not assigned, assign it */ assign->addr = try; list_add(&assign->head, &iface->dhcpv4_assignments); + syslog(LOG_DEBUG, "assigning mapped IP: %u.%u.%u.%u (try %u of %u)", + (assign->addr & 0xff000000) >> 24, + (assign->addr & 0x00ff0000) >> 16, + (assign->addr & 0x0000ff00) >> 8, + (assign->addr & 0x000000ff), i, count); return true; } - - struct dhcpv4_assignment *c; - list_for_each_entry(c, &iface->dhcpv4_assignments, head) { - if (c->addr > try) { - assign->addr = try; - list_add_tail(&assign->head, &c->head); - return true; - } else if (c->addr == try) { - if (i < tries - 1) - break; - else - ++try; - } - } + try = (((try - start) + 1) % count) + start; } + syslog(LOG_DEBUG, "can't assign any IP address -> address space is full"); return false; } @@ -447,22 +576,26 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface, struct dhcpv4_assignment *c, *n, *a = NULL; list_for_each_entry_safe(c, n, &iface->dhcpv4_assignments, head) { - if (c->addr == raddr && !memcmp(c->hwaddr, mac, 6)) { + if (!memcmp(c->hwaddr, mac, 6)) { a = c; - break; + if (c->addr == raddr) + break; } else if (c->valid_until < now) { list_del(&c->head); free(c); } } - bool update_state = false; if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) { bool assigned = !!a; size_t hostlen = strlen(hostname) + 1; if (!a && !iface->no_dynamic_dhcp) { // Create new binding a = calloc(1, sizeof(*a) + hostlen); + if (!a) { + syslog(LOG_ERR, "Failed to calloc binding on interface %s", iface->ifname); + return NULL; + } memcpy(a->hwaddr, mac, sizeof(a->hwaddr)); memcpy(a->hostname, hostname, hostlen); @@ -471,6 +604,10 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface, if (assigned && !a->hostname[0] && hostname) { a = realloc(a, sizeof(*a) + hostlen); + if (!a) { + syslog(LOG_ERR, "Failed to realloc binding on interface %s", iface->ifname); + return NULL; + } memcpy(a->hostname, hostname, hostlen); // Fixup list @@ -490,18 +627,14 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface, if (assigned && a) lease = a; } else if (msg == DHCPV4_MSG_RELEASE) { - if (a) { + if (a && a->valid_until != LONG_MAX) a->valid_until = 0; - update_state = true; - } - } else if (msg == DHCPV4_MSG_DECLINE) { + } else if (msg == DHCPV4_MSG_DECLINE && a && a->valid_until != LONG_MAX) { memset(a->hwaddr, 0, sizeof(a->hwaddr)); a->valid_until = now + 3600; // Block address for 1h - update_state = true; } - if (update_state) - dhcpv6_write_statefile(); + dhcpv6_write_statefile(); return lease; }