From f693e9b38f13575b988335e3324a50dcc8772d48 Mon Sep 17 00:00:00 2001 From: Tom Gundersen Date: Wed, 25 Nov 2015 17:29:30 +0100 Subject: sd-dhcp: parse error message in DECLINE or NAK If a client sends a DECLINE or a server sends a NAK, they can include a string with a message to explain the error. Parse this and print it at debug level. --- src/libsystemd-network/dhcp-internal.h | 3 +- src/libsystemd-network/dhcp-option.c | 109 +++++++++++++++++------------- src/libsystemd-network/dhcp-protocol.h | 1 + src/libsystemd-network/sd-dhcp-client.c | 9 +-- src/libsystemd-network/sd-dhcp-lease.c | 2 +- src/libsystemd-network/sd-dhcp-server.c | 6 +- src/libsystemd-network/test-dhcp-client.c | 6 +- src/libsystemd-network/test-dhcp-option.c | 22 ++---- 8 files changed, 84 insertions(+), 74 deletions(-) (limited to 'src/libsystemd-network') diff --git a/src/libsystemd-network/dhcp-internal.h b/src/libsystemd-network/dhcp-internal.h index a5daaa543a..7038212bcf 100644 --- a/src/libsystemd-network/dhcp-internal.h +++ b/src/libsystemd-network/dhcp-internal.h @@ -47,8 +47,7 @@ int dhcp_option_append(DHCPMessage *message, size_t size, size_t *offset, uint8_ typedef int (*dhcp_option_cb_t)(uint8_t code, uint8_t len, const void *option, void *userdata); -int dhcp_option_parse(DHCPMessage *message, size_t len, - dhcp_option_cb_t cb, void *userdata); +int dhcp_option_parse(DHCPMessage *message, size_t len, dhcp_option_cb_t cb, void *userdata, char **error_message); int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid, uint8_t type, uint16_t arp_type, size_t optlen, diff --git a/src/libsystemd-network/dhcp-option.c b/src/libsystemd-network/dhcp-option.c index a6c410ba91..1de7f3639c 100644 --- a/src/libsystemd-network/dhcp-option.c +++ b/src/libsystemd-network/dhcp-option.c @@ -24,6 +24,9 @@ #include #include +#include "alloc-util.h" +#include "utf8.h" + #include "dhcp-internal.h" static int option_append(uint8_t options[], size_t size, size_t *offset, @@ -139,72 +142,84 @@ int dhcp_option_append(DHCPMessage *message, size_t size, size_t *offset, } static int parse_options(const uint8_t options[], size_t buflen, uint8_t *overload, - uint8_t *message_type, dhcp_option_cb_t cb, + uint8_t *message_type, char **error_message, dhcp_option_cb_t cb, void *userdata) { uint8_t code, len; + const uint8_t *option; size_t offset = 0; while (offset < buflen) { - switch (options[offset]) { - case DHCP_OPTION_PAD: - offset++; + code = options[offset ++]; - break; + switch (code) { + case DHCP_OPTION_PAD: + continue; case DHCP_OPTION_END: return 0; + } - case DHCP_OPTION_MESSAGE_TYPE: - if (buflen < offset + 3) - return -ENOBUFS; + if (buflen < offset + 1) + return -ENOBUFS; + + len = options[offset ++]; - len = options[++offset]; + if (buflen < offset + len) + return -EINVAL; + + option = &options[offset]; + + switch (code) { + case DHCP_OPTION_MESSAGE_TYPE: if (len != 1) return -EINVAL; if (message_type) - *message_type = options[++offset]; - else - offset++; - - offset++; + *message_type = *option; break; - case DHCP_OPTION_OVERLOAD: - if (buflen < offset + 3) - return -ENOBUFS; - - len = options[++offset]; - if (len != 1) + case DHCP_OPTION_ERROR_MESSAGE: + if (len == 0) return -EINVAL; - if (overload) - *overload = options[++offset]; - else - offset++; + if (error_message) { + _cleanup_free_ char *string = NULL; - offset++; + /* Accept a trailing NUL byte */ + if (memchr(option, 0, len - 1)) + return -EINVAL; - break; + string = strndup((const char *) option, len); + if (!string) + return -ENOMEM; - default: - if (buflen < offset + 3) - return -ENOBUFS; + if (!ascii_is_valid(string)) + return -EINVAL; - code = options[offset]; - len = options[++offset]; + free(*error_message); + *error_message = string; + string = NULL; + } - if (buflen < ++offset + len) + break; + case DHCP_OPTION_OVERLOAD: + if (len != 1) return -EINVAL; - if (cb) - cb(code, len, &options[offset], userdata); + if (overload) + *overload = *option; - offset += len; + break; + + default: + if (cb) + cb(code, len, option, userdata); break; } + + offset += len; } if (offset < buflen) @@ -213,8 +228,8 @@ static int parse_options(const uint8_t options[], size_t buflen, uint8_t *overlo return 0; } -int dhcp_option_parse(DHCPMessage *message, size_t len, - dhcp_option_cb_t cb, void *userdata) { +int dhcp_option_parse(DHCPMessage *message, size_t len, dhcp_option_cb_t cb, void *userdata, char **_error_message) { + _cleanup_free_ char *error_message = NULL; uint8_t overload = 0; uint8_t message_type = 0; int r; @@ -227,27 +242,29 @@ int dhcp_option_parse(DHCPMessage *message, size_t len, len -= sizeof(DHCPMessage); - r = parse_options(message->options, len, &overload, &message_type, - cb, userdata); + r = parse_options(message->options, len, &overload, &message_type, &error_message, cb, userdata); if (r < 0) return r; if (overload & DHCP_OVERLOAD_FILE) { - r = parse_options(message->file, sizeof(message->file), - NULL, &message_type, cb, userdata); + r = parse_options(message->file, sizeof(message->file), NULL, &message_type, &error_message, cb, userdata); if (r < 0) return r; } if (overload & DHCP_OVERLOAD_SNAME) { - r = parse_options(message->sname, sizeof(message->sname), - NULL, &message_type, cb, userdata); + r = parse_options(message->sname, sizeof(message->sname), NULL, &message_type, &error_message, cb, userdata); if (r < 0) return r; } - if (message_type) - return message_type; + if (message_type == 0) + return -ENOMSG; + + if (_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE)) { + *_error_message = error_message; + error_message = NULL; + } - return -ENOMSG; + return message_type; } diff --git a/src/libsystemd-network/dhcp-protocol.h b/src/libsystemd-network/dhcp-protocol.h index 05bb5ae493..f65529a00e 100644 --- a/src/libsystemd-network/dhcp-protocol.h +++ b/src/libsystemd-network/dhcp-protocol.h @@ -132,6 +132,7 @@ enum { DHCP_OPTION_MESSAGE_TYPE = 53, DHCP_OPTION_SERVER_IDENTIFIER = 54, DHCP_OPTION_PARAMETER_REQUEST_LIST = 55, + DHCP_OPTION_ERROR_MESSAGE = 56, DHCP_OPTION_MAXIMUM_MESSAGE_SIZE = 57, DHCP_OPTION_RENEWAL_T1_TIME = 58, DHCP_OPTION_REBINDING_T2_TIME = 59, diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c index 66b8f101cf..d116180c16 100644 --- a/src/libsystemd-network/sd-dhcp-client.c +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -1082,7 +1082,7 @@ static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer, return r; } - r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease); + r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease, NULL); if (r != DHCP_OFFER) { log_dhcp_client(client, "received message was not an OFFER, ignoring"); return -ENOMSG; @@ -1121,7 +1121,7 @@ static int client_handle_forcerenew(sd_dhcp_client *client, DHCPMessage *force, size_t len) { int r; - r = dhcp_option_parse(force, len, NULL, NULL); + r = dhcp_option_parse(force, len, NULL, NULL, NULL); if (r != DHCP_FORCERENEW) return -ENOMSG; @@ -1133,6 +1133,7 @@ static int client_handle_forcerenew(sd_dhcp_client *client, DHCPMessage *force, static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack, size_t len) { _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL; + _cleanup_free_ char *error_message = NULL; int r; r = dhcp_lease_new(&lease); @@ -1147,9 +1148,9 @@ static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack, return r; } - r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease); + r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease, &error_message); if (r == DHCP_NAK) { - log_dhcp_client(client, "NAK"); + log_dhcp_client(client, "NAK: %s", strna(error_message)); return -EADDRNOTAVAIL; } diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c index 8befedc500..fccdc01bc3 100644 --- a/src/libsystemd-network/sd-dhcp-lease.c +++ b/src/libsystemd-network/sd-dhcp-lease.c @@ -661,7 +661,7 @@ int dhcp_lease_parse_options(uint8_t code, uint8_t len, const void *option, void break; default: - log_debug("Ignoring option DHCP option %i while parsing.", code); + log_debug("Ignoring option DHCP option %"PRIu8" while parsing.", code); break; } diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c index 3e2ecdaddd..587ff936ba 100644 --- a/src/libsystemd-network/sd-dhcp-server.c +++ b/src/libsystemd-network/sd-dhcp-server.c @@ -699,6 +699,7 @@ static int get_pool_offset(sd_dhcp_server *server, be32_t requested_ip) { int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, size_t length) { _cleanup_dhcp_request_free_ DHCPRequest *req = NULL; + _cleanup_free_ char *error_message = NULL; DHCPLease *existing_lease; int type, r; @@ -714,7 +715,7 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, if (!req) return -ENOMEM; - type = dhcp_option_parse(message, length, parse_request, req); + type = dhcp_option_parse(message, length, parse_request, req, &error_message); if (type < 0) return 0; @@ -784,8 +785,7 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, break; } case DHCP_DECLINE: - log_dhcp_server(server, "DECLINE (0x%x)", - be32toh(req->message->xid)); + log_dhcp_server(server, "DECLINE (0x%x): %s", be32toh(req->message->xid), strna(error_message)); /* TODO: make sure we don't offer this address again */ diff --git a/src/libsystemd-network/test-dhcp-client.c b/src/libsystemd-network/test-dhcp-client.c index 1200a7c251..4478147a83 100644 --- a/src/libsystemd-network/test-dhcp-client.c +++ b/src/libsystemd-network/test-dhcp-client.c @@ -223,7 +223,7 @@ int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port, const voi static int test_discover_message_verify(size_t size, struct DHCPMessage *dhcp) { int res; - res = dhcp_option_parse(dhcp, size, check_options, NULL); + res = dhcp_option_parse(dhcp, size, check_options, NULL, NULL); assert_se(res == DHCP_DISCOVER); if (verbose) @@ -390,7 +390,7 @@ static int test_addr_acq_recv_request(size_t size, DHCPMessage *request) { uint8_t *msg_bytes = (uint8_t *)request; int res; - res = dhcp_option_parse(request, size, check_options, NULL); + res = dhcp_option_parse(request, size, check_options, NULL, NULL); assert_se(res == DHCP_REQUEST); assert_se(xid == request->xid); @@ -420,7 +420,7 @@ static int test_addr_acq_recv_discover(size_t size, DHCPMessage *discover) { uint8_t *msg_bytes = (uint8_t *)discover; int res; - res = dhcp_option_parse(discover, size, check_options, NULL); + res = dhcp_option_parse(discover, size, check_options, NULL, NULL); assert_se(res == DHCP_DISCOVER); assert_se(msg_bytes[size - 1] == DHCP_OPTION_END); diff --git a/src/libsystemd-network/test-dhcp-option.c b/src/libsystemd-network/test-dhcp-option.c index 3607df63af..75d22c4df3 100644 --- a/src/libsystemd-network/test-dhcp-option.c +++ b/src/libsystemd-network/test-dhcp-option.c @@ -75,9 +75,8 @@ static const char *dhcp_type(int type) { static void test_invalid_buffer_length(void) { DHCPMessage message; - assert_se(dhcp_option_parse(&message, 0, NULL, NULL) == -EINVAL); - assert_se(dhcp_option_parse(&message, sizeof(DHCPMessage) - 1, NULL, NULL) - == -EINVAL); + assert_se(dhcp_option_parse(&message, 0, NULL, NULL, NULL) == -EINVAL); + assert_se(dhcp_option_parse(&message, sizeof(DHCPMessage) - 1, NULL, NULL, NULL) == -EINVAL); } static void test_message_init(void) { @@ -101,7 +100,7 @@ static void test_message_init(void) { assert_se(magic[2] == 83); assert_se(magic[3] == 99); - assert_se(dhcp_option_parse(message, len, NULL, NULL) >= 0); + assert_se(dhcp_option_parse(message, len, NULL, NULL, NULL) >= 0); } static DHCPMessage *create_message(uint8_t *options, uint16_t optlen, @@ -264,19 +263,12 @@ static void test_options(struct option_desc *desc) { buflen = sizeof(DHCPMessage) + optlen; if (!desc) { - assert_se((res = dhcp_option_parse(message, buflen, - test_options_cb, - NULL)) == -ENOMSG); + assert_se((res = dhcp_option_parse(message, buflen, test_options_cb, NULL, NULL)) == -ENOMSG); } else if (desc->success) { - assert_se((res = dhcp_option_parse(message, buflen, - test_options_cb, - desc)) >= 0); - assert_se(desc->pos == -1 && desc->filepos == -1 && - desc->snamepos == -1); + assert_se((res = dhcp_option_parse(message, buflen, test_options_cb, desc, NULL)) >= 0); + assert_se(desc->pos == -1 && desc->filepos == -1 && desc->snamepos == -1); } else - assert_se((res = dhcp_option_parse(message, buflen, - test_options_cb, - desc)) < 0); + assert_se((res = dhcp_option_parse(message, buflen, test_options_cb, desc, NULL)) < 0); if (verbose) printf("DHCP type %s\n", dhcp_type(res)); -- cgit v1.2.3-54-g00ecf