dhcp,network: support emitting DNS/NTP server information from DHCP server

For now, this is very simple and IP addresses have to be configured
manually.

4 files changed, 130 insertions, 1 deletions

diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index 0a72c14469..0d85005c8c 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -691,6 +691,27 @@ static int link_enter_set_addresses(Link *link) {
                                 return r;
                 }
 
+                if (link->network->dhcp_server_emit_dns) {
+
+                        if (link->network->n_dhcp_server_dns > 0) {
+                                r = sd_dhcp_server_set_dns(link->dhcp_server, link->network->dhcp_server_dns, link->network->n_dhcp_server_dns);
+                                if (r < 0)
+                                        log_link_warning_errno(link, r, "Failed to set DNS server for DHCP server, ignoring: %m");
+                        } else
+                                log_link_warning_errno(link, r, "DNS server emitting enabled, but no DNS servers set, ignoring: %m");
+                }
+
+
+                if (link->network->dhcp_server_emit_ntp) {
+
+                        if (link->network->n_dhcp_server_ntp > 0) {
+                                r = sd_dhcp_server_set_ntp(link->dhcp_server, link->network->dhcp_server_ntp, link->network->n_dhcp_server_ntp);
+                                if (r < 0)
+                                        log_link_warning_errno(link, r, "Failed to set NTP server for DHCP server, ignoring: %m");
+                        } else
+                                log_link_warning_errno(link, r, "NTP server emitting enabled, but no NTP servers set, ignoring: %m");
+                }
+
                 if (link->network->dhcp_server_emit_timezone) {
                         _cleanup_free_ char *buffer = NULL;
                         const char *tz;
diff --git a/src/network/networkd-network-gperf.gperf b/src/network/networkd-network-gperf.gperf
index 21e33efb42..108e892fb8 100644
--- a/src/network/networkd-network-gperf.gperf
+++ b/src/network/networkd-network-gperf.gperf
@@ -76,6 +76,10 @@ DHCP.RouteMetric,              config_parse_unsigned,                          0
 DHCP.UseTimezone,              config_parse_bool,                              0,                             offsetof(Network, dhcp_timezone)
 DHCPServer.MaxLeaseTimeSec,    config_parse_sec,                               0,                             offsetof(Network, dhcp_server_max_lease_time_usec)
 DHCPServer.DefaultLeaseTimeSec,config_parse_sec,                               0,                             offsetof(Network, dhcp_server_default_lease_time_usec)
+DHCPServer.EmitDNS,            config_parse_bool,                              0,                             offsetof(Network, dhcp_server_emit_dns)
+DHCPServer.DNS,                config_parse_dhcp_server_dns,                   0,                             0
+DHCPServer.EmitNTP,            config_parse_bool,                              0,                             offsetof(Network, dhcp_server_emit_ntp)
+DHCPServer.NTP,                config_parse_dhcp_server_ntp,                   0,                             0
 DHCPServer.EmitTimezone,       config_parse_bool,                              0,                             offsetof(Network, dhcp_server_emit_timezone)
 DHCPServer.Timezone,           config_parse_timezone,                          0,                             offsetof(Network, dhcp_server_timezone)
 Bridge.Cost,                   config_parse_unsigned,                          0,                             offsetof(Network, cost)
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index 11671b500d..848ec66151 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -260,6 +260,8 @@ void network_free(Network *network) {
         condition_free_list(network->match_arch);
 
         free(network->dhcp_server_timezone);
+        free(network->dhcp_server_dns);
+        free(network->dhcp_server_ntp);
 
         free(network);
 }
@@ -802,3 +804,97 @@ int config_parse_timezone(
 
         return 0;
 }
+
+int config_parse_dhcp_server_dns(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        Network *n = data;
+        const char *p = rvalue;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+
+        for (;;) {
+                _cleanup_free_ char *w = NULL;
+                struct in_addr a, *m;
+
+                r = extract_first_word(&p, &w, NULL, 0);
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Failed to extract word, ignoring: %s", rvalue);
+                        return 0;
+                }
+
+                if (r == 0)
+                        return 0;
+
+                if (inet_pton(AF_INET, w, &a) <= 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse DNS server address, ignoring: %s", w);
+                        continue;
+                }
+
+                m = realloc(n->dhcp_server_dns, (n->n_dhcp_server_dns + 1) * sizeof(struct in_addr));
+                if (!m)
+                        return log_oom();
+
+                m[n->n_dhcp_server_dns++] = a;
+                n->dhcp_server_dns = m;
+        }
+}
+
+int config_parse_dhcp_server_ntp(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        Network *n = data;
+        const char *p = rvalue;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+
+        for (;;) {
+                _cleanup_free_ char *w = NULL;
+                struct in_addr a, *m;
+
+                r = extract_first_word(&p, &w, NULL, 0);
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, r, line, "Failed to extract word, ignoring: %s", rvalue);
+                        return 0;
+                }
+
+                if (r == 0)
+                        return 0;
+
+                if (inet_pton(AF_INET, w, &a) <= 0) {
+                        log_syntax(unit, LOG_ERR, filename, r, line, "Failed to parse NTP server address, ignoring: %s", w);
+                        continue;
+                }
+
+                m = realloc(n->dhcp_server_ntp, (n->n_dhcp_server_ntp + 1) * sizeof(struct in_addr));
+                if (!m)
+                        return log_oom();
+
+                m[n->n_dhcp_server_ntp++] = a;
+                n->dhcp_server_ntp = m;
+        }
+}
diff --git a/src/network/networkd-network.h b/src/network/networkd-network.h
index 7d2add300f..d691cc3a45 100644
--- a/src/network/networkd-network.h
+++ b/src/network/networkd-network.h
@@ -93,8 +93,14 @@ struct Network {
 
         /* DHCP Server Support */
         bool dhcp_server;
-        char *dhcp_server_timezone;
+        bool dhcp_server_emit_dns;
+        struct in_addr *dhcp_server_dns;
+        unsigned n_dhcp_server_dns;
+        bool dhcp_server_emit_ntp;
+        struct in_addr *dhcp_server_ntp;
+        unsigned n_dhcp_server_ntp;
         bool dhcp_server_emit_timezone;
+        char *dhcp_server_timezone;
         usec_t dhcp_server_default_lease_time_usec, dhcp_server_max_lease_time_usec;
 
         /* IPV4LL Support */
@@ -156,6 +162,8 @@ int config_parse_ipv6token(const char *unit, const char *filename, unsigned line
 int config_parse_ipv6_privacy_extensions(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_hostname(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_timezone(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+int config_parse_dhcp_server_dns(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+int config_parse_dhcp_server_ntp(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 
 /* Legacy IPv4LL support */
 int config_parse_ipv4ll(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);