From 223bc97f61f2fd5efbccede0837a374c1669e864 Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Thu, 22 Nov 2007 00:58:49 +0000 Subject: udhcpc: an option to perform ARP check (Jonas Danielsson ) configurable, ~+300 bytes when on. --- networking/udhcp/Config.in | 10 +++++++ networking/udhcp/Kbuild | 6 ++++ networking/udhcp/arpping.c | 29 ++++++++++++------ networking/udhcp/clientpacket.c | 16 ++++++++++ networking/udhcp/common.h | 2 +- networking/udhcp/dhcpc.c | 65 +++++++++++++++++++++++++++++++++-------- networking/udhcp/dhcpc.h | 7 +++-- networking/udhcp/signalpipe.c | 2 +- 8 files changed, 111 insertions(+), 26 deletions(-) (limited to 'networking/udhcp') diff --git a/networking/udhcp/Config.in b/networking/udhcp/Config.in index 76b0780..734db65 100644 --- a/networking/udhcp/Config.in +++ b/networking/udhcp/Config.in @@ -54,6 +54,16 @@ config APP_UDHCPC See http://udhcp.busybox.net for further details. +config FEATURE_UDHCPC_ARPING + bool "Ask udhcpc to verify that the offered address is free, using arpping" + default y + depends on APP_UDHCPC + help + If selected, udhcpc will use arpping to make sure the offered address + is really available. The client will DHCPDECLINE the offer if the + address is in use, and restart the discover process. + + config FEATURE_UDHCP_DEBUG bool "Compile udhcp with noisy debugging messages" default n diff --git a/networking/udhcp/Kbuild b/networking/udhcp/Kbuild index aed40b9..7d47470 100644 --- a/networking/udhcp/Kbuild +++ b/networking/udhcp/Kbuild @@ -10,10 +10,16 @@ lib-$(CONFIG_APP_UDHCPC) += common.o options.o packet.o \ signalpipe.o socket.o lib-$(CONFIG_APP_UDHCPD) += common.o options.o packet.o \ signalpipe.o socket.o + lib-$(CONFIG_APP_UDHCPC) += dhcpc.o clientpacket.o clientsocket.o \ script.o + +UDHCPC_NEEDS_ARPING-$(CONFIG_FEATURE_UDHCPC_ARPING) = y +lib-$(UDHCPC_NEEDS_ARPING) += arpping.o + lib-$(CONFIG_APP_UDHCPD) += dhcpd.o arpping.o files.o leases.o \ serverpacket.o static_leases.o + lib-$(CONFIG_APP_DUMPLEASES) += dumpleases.o lib-$(CONFIG_APP_DHCPRELAY) += dhcprelay.o lib-$(CONFIG_FEATURE_RFC3397) += domain_codec.o diff --git a/networking/udhcp/arpping.c b/networking/udhcp/arpping.c index 7b702d8..45597c0 100644 --- a/networking/udhcp/arpping.c +++ b/networking/udhcp/arpping.c @@ -32,12 +32,16 @@ struct arpMsg { uint8_t pad[18]; /* 2a pad for min. ethernet payload (60 bytes) */ } ATTRIBUTE_PACKED; +enum { + ARP_MSG_SIZE = 0x2a +}; + /* Returns 1 if no reply received */ int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *interface) { - int timeout_ms = 2000; + int timeout_ms; struct pollfd pfd[1]; #define s (pfd[0].fd) /* socket */ int rv = 1; /* "no reply received" yet */ @@ -51,7 +55,7 @@ int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *i } if (setsockopt_broadcast(s) == -1) { - bb_perror_msg("cannot setsocketopt on raw socket"); + bb_perror_msg("cannot enable bcast on raw socket"); goto ret; } @@ -67,28 +71,35 @@ int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *i arp.operation = htons(ARPOP_REQUEST); /* ARP op code */ memcpy(arp.sHaddr, from_mac, 6); /* source hardware address */ memcpy(arp.sInaddr, &from_ip, sizeof(from_ip)); /* source IP address */ - /* tHaddr */ /* target hardware address */ + /* tHaddr is zero-fiiled */ /* target hardware address */ memcpy(arp.tInaddr, &test_ip, sizeof(test_ip)); /* target IP address */ memset(&addr, 0, sizeof(addr)); safe_strncpy(addr.sa_data, interface, sizeof(addr.sa_data)); - if (sendto(s, &arp, sizeof(arp), 0, &addr, sizeof(addr)) < 0) + if (sendto(s, &arp, sizeof(arp), 0, &addr, sizeof(addr)) < 0) { + // TODO: error message? caller didn't expect us to fail, + // just returning 1 "no reply received" misleads it. goto ret; + } /* wait for arp reply, and check it */ + timeout_ms = 2000; do { int r; unsigned prevTime = monotonic_us(); pfd[0].events = POLLIN; r = safe_poll(pfd, 1, timeout_ms); - if (r < 0) { + if (r < 0) break; - } else if (r) { - if (read(s, &arp, sizeof(arp)) < 0) + if (r) { + r = read(s, &arp, sizeof(arp)); + if (r < 0) break; - if (arp.operation == htons(ARPOP_REPLY) - && memcmp(arp.tHaddr, from_mac, 6) == 0 + if (r >= ARP_MSG_SIZE + && arp.operation == htons(ARPOP_REPLY) + /* don't check it: Linux doesn't return proper tHaddr (fixed in 2.6.24?) */ + /* && memcmp(arp.tHaddr, from_mac, 6) == 0 */ && *((uint32_t *) arp.sInaddr) == test_ip ) { rv = 0; diff --git a/networking/udhcp/clientpacket.c b/networking/udhcp/clientpacket.c index 42b4895..e7eeb58 100644 --- a/networking/udhcp/clientpacket.c +++ b/networking/udhcp/clientpacket.c @@ -69,6 +69,22 @@ static void add_requests(struct dhcpMessage *packet) } +#if ENABLE_FEATURE_UDHCPC_ARPING +/* Unicast a DHCP decline message */ +int send_decline(uint32_t xid, uint32_t server) +{ + struct dhcpMessage packet; + + init_packet(&packet, DHCPDECLINE); + packet.xid = xid; + add_requests(&packet); + + bb_info_msg("Sending decline..."); + + return udhcp_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, + SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex); +} +#endif /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */ int send_discover(uint32_t xid, uint32_t requested) diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h index 4864c85..179c21f 100644 --- a/networking/udhcp/common.h +++ b/networking/udhcp/common.h @@ -76,7 +76,7 @@ void udhcp_run_script(struct dhcpMessage *packet, const char *name); void udhcp_sp_setup(void); int udhcp_sp_fd_set(fd_set *rfds, int extra_fd); -int udhcp_sp_read(fd_set *rfds); +int udhcp_sp_read(const fd_set *rfds); int raw_socket(int ifindex); int read_interface(const char *interface, int *ifindex, uint32_t *addr, uint8_t *arp); int listen_socket(/*uint32_t ip,*/ int port, const char *inf); diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index c6f9fe4..b3b8945 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -145,6 +145,13 @@ int udhcpc_main(int argc, char **argv) { uint8_t *temp, *message; char *str_c, *str_V, *str_h, *str_F, *str_r, *str_T, *str_A, *str_t; + int tryagain_timeout = 60; + int discover_timeout = 3; + int discover_retries = 3; +#if ENABLE_FEATURE_UDHCPC_ARPING + int decline_wait = 10; + char *str_W; +#endif uint32_t xid = 0; uint32_t lease = 0; /* can be given as 32-bit quantity */ unsigned t1 = 0, t2 = 0; /* what a wonderful names */ @@ -180,6 +187,10 @@ int udhcpc_main(int argc, char **argv) OPT_v = 1 << 17, OPT_S = 1 << 18, OPT_A = 1 << 19, +#if ENABLE_FEATURE_UDHCPC_ARPING + OPT_a = 1 << 20, + OPT_W = 1 << 21, +#endif }; #if ENABLE_GETOPT_LONG static const char udhcpc_longopts[] ALIGN1 = @@ -203,14 +214,15 @@ int udhcpc_main(int argc, char **argv) "retries\0" Required_argument "t" "tryagain\0" Required_argument "A" "syslog\0" No_argument "S" +#if ENABLE_FEATURE_UDHCPC_ARPING + "arping\0" No_argument "a" + "wait\0" Required_argument "W" +#endif ; #endif /* Default options. */ client_config.interface = "eth0"; client_config.script = DEFAULT_SCRIPT; - client_config.retries = 3; - client_config.timeout = 3; - client_config.tryagain = 60; /* Parse command line */ opt_complementary = "c--C:C--c" // mutually exclusive @@ -218,10 +230,12 @@ int udhcpc_main(int argc, char **argv) #if ENABLE_GETOPT_LONG applet_long_options = udhcpc_longopts; #endif - opt = getopt32(argv, "c:CV:fbH:h:F:i:np:qRr:s:T:t:vSA:", - &str_c, &str_V, &str_h, &str_h, &str_F, + opt = getopt32(argv, "c:CV:fbH:h:F:i:np:qRr:s:T:t:vSA:" + USE_FEATURE_UDHCPC_ARPING("aW:") + , &str_c, &str_V, &str_h, &str_h, &str_F, &client_config.interface, &client_config.pidfile, &str_r, &client_config.script, &str_T, &str_t, &str_A + USE_FEATURE_UDHCPC_ARPING(, &str_W) ); if (opt & OPT_c) @@ -259,11 +273,11 @@ int udhcpc_main(int argc, char **argv) requested_ip = inet_addr(str_r); // if (opt & OPT_s) client_config.script = ... if (opt & OPT_T) - client_config.timeout = xatoi_u(str_T); + discover_timeout = xatoi_u(str_T); if (opt & OPT_t) - client_config.retries = xatoi_u(str_t); + discover_retries = xatoi_u(str_t); if (opt & OPT_A) - client_config.tryagain = xatoi_u(str_A); + tryagain_timeout = xatoi_u(str_A); if (opt & OPT_v) { puts("version "BB_VER); return 0; @@ -274,6 +288,11 @@ int udhcpc_main(int argc, char **argv) logmode |= LOGMODE_SYSLOG; } +#if ENABLE_FEATURE_UDHCPC_ARPING + if (opt & OPT_W) + decline_wait = xatou_range(str_W, 10, INT_MAX); +#endif + if (read_interface(client_config.interface, &client_config.ifindex, NULL, client_config.arp)) return 1; @@ -339,14 +358,14 @@ int udhcpc_main(int argc, char **argv) /* timeout dropped to zero */ switch (state) { case INIT_SELECTING: - if (packet_num < client_config.retries) { + if (packet_num < discover_retries) { if (packet_num == 0) xid = random_xid(); /* send discover packet */ send_discover(xid, requested_ip); /* broadcast */ - timeout = now + client_config.timeout; + timeout = now + discover_timeout; packet_num++; } else { udhcp_run_script(NULL, "leasefail"); @@ -360,12 +379,12 @@ int udhcpc_main(int argc, char **argv) } /* wait to try again */ packet_num = 0; - timeout = now + client_config.tryagain; + timeout = now + tryagain_timeout; } break; case RENEW_REQUESTED: case REQUESTING: - if (packet_num < client_config.retries) { + if (packet_num < discover_retries) { /* send request packet */ if (state == RENEW_REQUESTED) send_renew(xid, server_addr, requested_ip); /* unicast */ @@ -491,6 +510,28 @@ int udhcpc_main(int argc, char **argv) lease = ntohl(lease); } +#if ENABLE_FEATURE_UDHCPC_ARPING + if (opt & OPT_a) { + if (!arpping(packet.yiaddr, + (uint32_t) 0, + client_config.arp, + client_config.interface) + ) { + bb_info_msg("offered address is in use," + " declining"); + send_decline(xid, server_addr); + + if (state != REQUESTING) + udhcp_run_script(NULL, "deconfig"); + state = INIT_SELECTING; + requested_ip = 0; + packet_num = 0; + change_mode(LISTEN_RAW); + timeout = now + decline_wait; + break; + } + } +#endif /* enter bound state */ t1 = lease / 2; diff --git a/networking/udhcp/dhcpc.h b/networking/udhcp/dhcpc.h index 72a8bd9..c0172a8 100644 --- a/networking/udhcp/dhcpc.h +++ b/networking/udhcp/dhcpc.h @@ -1,5 +1,6 @@ /* vi: set sw=4 ts=4: */ /* dhcpc.h */ + #ifndef _DHCPC_H #define _DHCPC_H @@ -28,9 +29,6 @@ struct client_config_t { uint8_t *hostname; /* Optional hostname to use */ uint8_t *fqdn; /* Optional fully qualified domain name to use */ int ifindex; /* Index number of the interface to use */ - int retries; /* Max number of request packets */ - int timeout; /* Number of seconds to try to get a lease */ - int tryagain; /* Number of seconds to try to get a lease */ uint8_t arp[6]; /* Our arp address */ }; @@ -42,6 +40,9 @@ struct client_config_t { uint32_t random_xid(void); int send_discover(uint32_t xid, uint32_t requested); int send_selecting(uint32_t xid, uint32_t server, uint32_t requested); +#if ENABLE_FEATURE_UDHCPC_ARPING +int send_decline(uint32_t xid, uint32_t server); +#endif int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr); int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr); int send_release(uint32_t server, uint32_t ciaddr); diff --git a/networking/udhcp/signalpipe.c b/networking/udhcp/signalpipe.c index fafd208..845aa3a 100644 --- a/networking/udhcp/signalpipe.c +++ b/networking/udhcp/signalpipe.c @@ -66,7 +66,7 @@ int udhcp_sp_fd_set(fd_set *rfds, int extra_fd) /* Read a signal from the signal pipe. Returns 0 if there is * no signal, -1 on error (and sets errno appropriately), and * your signal on success */ -int udhcp_sp_read(fd_set *rfds) +int udhcp_sp_read(const fd_set *rfds) { unsigned char sig; -- cgit v1.1