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authorTom Gundersen <teg@jklm.no>2015-11-25 17:29:30 +0100
committerTom Gundersen <teg@jklm.no>2015-11-25 18:30:31 +0100
commitf693e9b38f13575b988335e3324a50dcc8772d48 (patch)
treefee9386c766685ad7cf7c0dc15c78711d4dd8855 /src
parentcddf4d81eacfc81cf761619fcb67bc07a744a6d1 (diff)
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.
Diffstat (limited to 'src')
-rw-r--r--src/libsystemd-network/dhcp-internal.h3
-rw-r--r--src/libsystemd-network/dhcp-option.c109
-rw-r--r--src/libsystemd-network/dhcp-protocol.h1
-rw-r--r--src/libsystemd-network/sd-dhcp-client.c9
-rw-r--r--src/libsystemd-network/sd-dhcp-lease.c2
-rw-r--r--src/libsystemd-network/sd-dhcp-server.c6
-rw-r--r--src/libsystemd-network/test-dhcp-client.c6
-rw-r--r--src/libsystemd-network/test-dhcp-option.c22
8 files changed, 84 insertions, 74 deletions
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 <stdio.h>
#include <string.h>
+#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));