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dhcp6: parse the FQDN option

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Parse option 39 (Client Fully Qualified Domain Name, RFC 4704) from the DHCP
reply, which specifies the FQDN assigned by the server to the client.
This commit is contained in:
Beniamino Galvani 2020-07-28 07:48:11 +02:00
parent af710b535b
commit c43eea9f2e
7 changed files with 192 additions and 51 deletions
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5
src/libsystemd-network/dhcp6-internal.h
View file

@ -109,8 +109,9 @@ int dhcp6_option_parse_ia(DHCP6Option *iaoption, DHCP6IA *ia, uint16_t *ret_stat
int dhcp6_option_parse_ip6addrs(uint8_t *optval, uint16_t optlen,
struct in6_addr **addrs, size_t count,
size_t *allocated);
int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen,
char ***str_arr);
int dhcp6_option_parse_domainname_list(const uint8_t *optval, uint16_t optlen,
char ***str_arr);
int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen, char **str);
int dhcp6_network_bind_udp_socket(int ifindex, struct in6_addr *address);
int dhcp6_network_send_udp_socket(int s, struct in6_addr *address,

2
src/libsystemd-network/dhcp6-lease-internal.h
View file

@ -35,6 +35,7 @@ struct sd_dhcp6_lease {
size_t ntp_allocated;
char **ntp_fqdn;
size_t ntp_fqdn_count;
char *fqdn;
};
int dhcp6_lease_ia_rebind_expire(const DHCP6IA *ia, uint32_t *expire);
@ -57,5 +58,6 @@ int dhcp6_lease_set_domains(sd_dhcp6_lease *lease, uint8_t *optval,
int dhcp6_lease_set_ntp(sd_dhcp6_lease *lease, uint8_t *optval, size_t optlen);
int dhcp6_lease_set_sntp(sd_dhcp6_lease *lease, uint8_t *optval,
size_t optlen) ;
int dhcp6_lease_set_fqdn(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen);
int dhcp6_lease_new(sd_dhcp6_lease **ret);

130
src/libsystemd-network/dhcp6-option.c
View file

@ -642,8 +642,87 @@ int dhcp6_option_parse_ip6addrs(uint8_t *optval, uint16_t optlen,
return count;
}
int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen, char ***str_arr) {
size_t pos = 0, idx = 0;
static int parse_domain(const uint8_t **data, uint16_t *len, char **out_domain) {
_cleanup_free_ char *ret = NULL;
size_t n = 0, allocated = 0;
const uint8_t *optval = *data;
uint16_t optlen = *len;
bool first = true;
int r;
if (optlen <= 1)
return -ENODATA;
for (;;) {
const char *label;
uint8_t c;
if (optlen == 0)
break;
c = *optval;
optval++;
optlen--;
if (c == 0)
/* End label */
break;
if (c > 63)
return -EBADMSG;
if (c > optlen)
return -EMSGSIZE;
/* Literal label */
label = (const char *)optval;
optval += c;
optlen -= c;
if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX))
return -ENOMEM;
if (first)
first = false;
else
ret[n++] = '.';
r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX);
if (r < 0)
return r;
n += r;
}
if (n) {
if (!GREEDY_REALLOC(ret, allocated, n + 1))
return -ENOMEM;
ret[n] = 0;
}
*out_domain = TAKE_PTR(ret);
*data = optval;
*len = optlen;
return n;
}
int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen, char **str) {
_cleanup_free_ char *domain = NULL;
int r;
r = parse_domain(&optval, &optlen, &domain);
if (r < 0)
return r;
if (r == 0)
return -ENODATA;
if (optlen != 0)
return -EINVAL;
*str = TAKE_PTR(domain);
return 0;
}
int dhcp6_option_parse_domainname_list(const uint8_t *optval, uint16_t optlen, char ***str_arr) {
size_t idx = 0;
_cleanup_strv_free_ char **names = NULL;
int r;
@ -652,52 +731,15 @@ int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen, char *
if (optval[optlen - 1] != '\0')
return -EINVAL;
while (pos < optlen) {
while (optlen > 0) {
_cleanup_free_ char *ret = NULL;
size_t n = 0, allocated = 0;
bool first = true;
for (;;) {
const char *label;
uint8_t c;
c = optval[pos++];
if (c == 0)
/* End of name */
break;
if (c > 63)
return -EBADMSG;
/* Literal label */
label = (const char *)&optval[pos];
pos += c;
if (pos >= optlen)
return -EMSGSIZE;
if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX))
return -ENOMEM;
if (first)
first = false;
else
ret[n++] = '.';
r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX);
if (r < 0)
return r;
n += r;
}
if (n == 0)
r = parse_domain(&optval, &optlen, &ret);
if (r < 0)
return r;
if (r == 0)
continue;
if (!GREEDY_REALLOC(ret, allocated, n + 1))
return -ENOMEM;
ret[n] = 0;
r = strv_extend(&names, ret);
if (r < 0)
return r;

7
src/libsystemd-network/sd-dhcp6-client.c
View file

@ -1282,6 +1282,13 @@ static int client_parse_message(
break;
case SD_DHCP6_OPTION_FQDN:
r = dhcp6_lease_set_fqdn(lease, optval, optlen);
if (r < 0)
return r;
break;
case SD_DHCP6_OPTION_INFORMATION_REFRESH_TIME:
if (optlen != 4)
return -EINVAL;

39
src/libsystemd-network/sd-dhcp6-lease.c
View file

@ -236,7 +236,7 @@ int dhcp6_lease_set_domains(sd_dhcp6_lease *lease, uint8_t *optval,
if (!optlen)
return 0;
r = dhcp6_option_parse_domainname(optval, optlen, &domains);
r = dhcp6_option_parse_domainname_list(optval, optlen, &domains);
if (r < 0)
return 0;
@ -294,8 +294,8 @@ int dhcp6_lease_set_ntp(sd_dhcp6_lease *lease, uint8_t *optval, size_t optlen) {
break;
case DHCP6_NTP_SUBOPTION_SRV_FQDN:
r = dhcp6_option_parse_domainname(subval, sublen,
&servers);
r = dhcp6_option_parse_domainname_list(subval, sublen,
&servers);
if (r < 0)
return 0;
@ -365,6 +365,38 @@ int sd_dhcp6_lease_get_ntp_fqdn(sd_dhcp6_lease *lease, char ***ntp_fqdn) {
return -ENOENT;
}
int dhcp6_lease_set_fqdn(sd_dhcp6_lease *lease, const uint8_t *optval,
size_t optlen) {
int r;
char *fqdn;
assert_return(lease, -EINVAL);
assert_return(optval, -EINVAL);
if (optlen < 2)
return -ENODATA;
/* Ignore the flags field, it doesn't carry any useful
information for clients. */
r = dhcp6_option_parse_domainname(optval + 1, optlen - 1, &fqdn);
if (r < 0)
return r;
return free_and_replace(lease->fqdn, fqdn);
}
int sd_dhcp6_lease_get_fqdn(sd_dhcp6_lease *lease, const char **fqdn) {
assert_return(lease, -EINVAL);
assert_return(fqdn, -EINVAL);
if (lease->fqdn) {
*fqdn = lease->fqdn;
return 0;
}
return -ENOENT;
}
static sd_dhcp6_lease *dhcp6_lease_free(sd_dhcp6_lease *lease) {
assert(lease);
@ -373,6 +405,7 @@ static sd_dhcp6_lease *dhcp6_lease_free(sd_dhcp6_lease *lease) {
dhcp6_lease_free_ia(&lease->pd);
free(lease->dns);
free(lease->fqdn);
lease->domains = strv_free(lease->domains);

59
src/libsystemd-network/test-dhcp6-client.c
View file

@ -20,6 +20,8 @@
#include "macro.h"
#include "memory-util.h"
#include "socket-util.h"
#include "string-util.h"
#include "strv.h"
#include "tests.h"
#include "time-util.h"
#include "virt.h"
@ -106,6 +108,52 @@ static int test_client_basic(sd_event *e) {
return 0;
}
static int test_parse_domain(sd_event *e) {
uint8_t *data;
char *domain;
char **list;
int r;
log_debug("/* %s */", __func__);
data = (uint8_t []) { 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'c', 'o', 'm', 0 };
r = dhcp6_option_parse_domainname(data, 13, &domain);
assert_se(r == 0);
assert_se(domain);
assert_se(streq(domain, "example.com"));
free(domain);
data = (uint8_t []) { 4, 't', 'e', 's', 't' };
r = dhcp6_option_parse_domainname(data, 5, &domain);
assert_se(r == 0);
assert_se(domain);
assert_se(streq(domain, "test"));
free(domain);
data = (uint8_t []) { 0 };
r = dhcp6_option_parse_domainname(data, 1, &domain);
assert_se(r < 0);
data = (uint8_t []) { 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'c', 'o', 'm', 0,
6, 'f', 'o', 'o', 'b', 'a', 'r', 0 };
r = dhcp6_option_parse_domainname_list(data, 21, &list);
assert_se(r == 2);
assert_se(list);
assert_se(streq(list[0], "example.com"));
assert_se(streq(list[1], "foobar"));
strv_free(list);
data = (uint8_t []) { 1, 'a', 0, 20, 'b', 'c' };
r = dhcp6_option_parse_domainname_list(data, 6, &list);
assert_se(r < 0);
data = (uint8_t []) { 0 , 0 };
r = dhcp6_option_parse_domainname_list(data, 2, &list);
assert_se(r < 0);
return 0;
}
static int test_option(sd_event *e) {
uint8_t packet[] = {
'F', 'O', 'O',
@ -330,7 +378,7 @@ static uint8_t msg_advertise[198] = {
0x53, 0x00, 0x07, 0x00, 0x01, 0x00
};
static uint8_t msg_reply[173] = {
static uint8_t msg_reply[191] = {
0x07, 0xf7, 0x4e, 0x57, 0x00, 0x02, 0x00, 0x0e,
0x00, 0x01, 0x00, 0x01, 0x19, 0x40, 0x5c, 0x53,
0x78, 0x2b, 0xcb, 0xb3, 0x6d, 0x53, 0x00, 0x01,
@ -352,7 +400,9 @@ static uint8_t msg_reply[173] = {
0x61, 0x62, 0x05, 0x69, 0x6e, 0x74, 0x72, 0x61,
0x00, 0x00, 0x1f, 0x00, 0x10, 0x20, 0x01, 0x0d,
0xb8, 0xde, 0xad, 0xbe, 0xef, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x01
0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x27, 0x00,
0x0e, 0x01, 0x06, 0x63, 0x6c, 0x69, 0x65, 0x6e,
0x74, 0x05, 0x69, 0x6e, 0x74, 0x72, 0x61
};
static uint8_t fqdn_wire[16] = {
@ -747,6 +797,7 @@ static void test_client_information_cb(sd_dhcp6_client *client, int event,
const struct in6_addr *addrs;
struct in6_addr address = { { { 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01 } } };
char **domains;
const char *fqdn;
log_debug("/* %s */", __func__);
@ -759,6 +810,9 @@ static void test_client_information_cb(sd_dhcp6_client *client, int event,
assert_se(!strcmp("lab.intra", domains[0]));
assert_se(domains[1] == NULL);
assert_se(sd_dhcp6_lease_get_fqdn(lease, &fqdn) >= 0);
assert_se(streq(fqdn, "client.intra"));
assert_se(sd_dhcp6_lease_get_dns(lease, &addrs) == 1);
assert_se(!memcmp(addrs, &msg_advertise[124], 16));
@ -945,6 +999,7 @@ int main(int argc, char *argv[]) {
test_option_status(e);
test_advertise_option(e);
test_client_solicit(e);
test_parse_domain(e);
return 0;
}

1
src/systemd/sd-dhcp6-lease.h
View file

@ -43,6 +43,7 @@ int sd_dhcp6_lease_get_dns(sd_dhcp6_lease *lease, const struct in6_addr **addrs)
int sd_dhcp6_lease_get_domains(sd_dhcp6_lease *lease, char ***domains);
int sd_dhcp6_lease_get_ntp_addrs(sd_dhcp6_lease *lease, const struct in6_addr **addrs);
int sd_dhcp6_lease_get_ntp_fqdn(sd_dhcp6_lease *lease, char ***ntp_fqdn);
int sd_dhcp6_lease_get_fqdn(sd_dhcp6_lease *lease, const char **fqdn);
sd_dhcp6_lease *sd_dhcp6_lease_ref(sd_dhcp6_lease *lease);
sd_dhcp6_lease *sd_dhcp6_lease_unref(sd_dhcp6_lease *lease);