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network: fallback on resolved resolv.conf for DHCP server settings

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This commit is contained in:
Marc-André Lureau 2020-04-28 17:59:47 +02:00
parent 2d95d81f7b
commit dd1d306058
1 changed files with 88 additions and 2 deletions
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90
src/network/networkd-dhcp-server.c
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@ -2,14 +2,17 @@
#include "sd-dhcp-server.h"
#include "fd-util.h"
#include "fileio.h"
#include "networkd-dhcp-server.h"
#include "networkd-link.h"
#include "networkd-manager.h"
#include "networkd-network.h"
#include "parse-util.h"
#include "strv.h"
#include "socket-netlink.h"
#include "string-table.h"
#include "string-util.h"
#include "strv.h"
static Address* link_find_dhcp_server_address(Link *link) {
Address *address;
@ -174,6 +177,87 @@ static int link_push_uplink_to_dhcp_server(
return sd_dhcp_server_set_servers(s, what, addresses, n_addresses);
}
static int dhcp4_server_parse_dns_server_string_and_warn(Link *l, const char *string, struct in_addr **addresses, size_t *n_allocated, size_t *n_addresses) {
for (;;) {
_cleanup_free_ char *word = NULL, *server_name = NULL;
union in_addr_union address;
int family, r, ifindex = 0;
r = extract_first_word(&string, &word, NULL, 0);
if (r < 0)
return r;
if (r == 0)
break;
r = in_addr_ifindex_name_from_string_auto(word, &family, &address, &ifindex, &server_name);
if (r < 0) {
log_warning_errno(r, "Failed to parse DNS server address '%s', ignoring: %m", word);
continue;
}
/* Only look for IPv4 addresses */
if (family != AF_INET)
continue;
/* Never propagate obviously borked data */
if (in4_addr_is_null(&address.in) || in4_addr_is_localhost(&address.in))
continue;
if (!GREEDY_REALLOC(*addresses, *n_allocated, *n_addresses + 1))
return log_oom();
(*addresses)[(*n_addresses)++] = address.in;
}
return 0;
}
static int dhcp4_server_set_dns_from_resolve_conf(Link *link) {
_cleanup_free_ struct in_addr *addresses = NULL;
size_t n_addresses = 0, n_allocated = 0;
_cleanup_fclose_ FILE *f = NULL;
int n = 0, r;
f = fopen(PRIVATE_UPLINK_RESOLV_CONF, "re");
if (!f) {
if (errno == ENOENT)
return 0;
return log_warning_errno(errno, "Failed to open " PRIVATE_UPLINK_RESOLV_CONF ": %m");
}
for (;;) {
_cleanup_free_ char *line = NULL;
const char *a;
char *l;
r = read_line(f, LONG_LINE_MAX, &line);
if (r < 0)
return log_error_errno(r, "Failed to read " PRIVATE_UPLINK_RESOLV_CONF ": %m");
if (r == 0)
break;
n++;
l = strstrip(line);
if (IN_SET(*l, '#', ';', 0))
continue;
a = first_word(l, "nameserver");
if (!a)
continue;
r = dhcp4_server_parse_dns_server_string_and_warn(link, a, &addresses, &n_allocated, &n_addresses);
if (r < 0)
log_warning_errno(r, "Failed to parse DNS server address '%s', ignoring.", a);
}
if (n_addresses <= 0)
return 0;
return sd_dhcp_server_set_dns(link->dhcp_server, addresses, n_addresses);
}
int dhcp4_server_configure(Link *link) {
bool acquired_uplink = false;
sd_dhcp_option *p;
@ -267,8 +351,10 @@ int dhcp4_server_configure(Link *link) {
"Not emitting %s on link, couldn't find suitable uplink.",
dhcp_lease_info_to_string(n));
r = 0;
} else
} else if (uplink->network)
r = link_push_uplink_to_dhcp_server(uplink, n, link->dhcp_server);
else if (n == SD_DHCP_LEASE_DNS_SERVERS)
r = dhcp4_server_set_dns_from_resolve_conf(link);
}
if (r < 0)
log_link_warning_errno(link, r,