util: introduce bus_mesage_read_dns_servers()

2 files changed, 120 insertions, 0 deletions

diff --git a/src/shared/bus-message-util.c b/src/shared/bus-message-util.c
index 2b13001c32..4151b91aec 100644
--- a/src/shared/bus-message-util.c
+++ b/src/shared/bus-message-util.c
@@ -2,6 +2,8 @@
 
 #include "bus-message-util.h"
 
+#include "resolve-util.h"
+
 int bus_message_read_family(sd_bus_message *message, sd_bus_error *error, int *ret) {
         int family, r;
 
@@ -48,3 +50,113 @@ int bus_message_read_in_addr_auto(sd_bus_message *message, sd_bus_error *error,
                 memcpy(ret_addr, d, sz);
         return 0;
 }
+
+static int bus_message_read_dns_one(
+                        sd_bus_message *message,
+                        sd_bus_error *error,
+                        bool extended,
+                        int *ret_family,
+                        union in_addr_union *ret_address,
+                        uint16_t *ret_port,
+                        const char **ret_server_name) {
+        const char *server_name = NULL;
+        union in_addr_union a;
+        uint16_t port = 0;
+        int family, r;
+
+        assert(message);
+        assert(ret_family);
+        assert(ret_address);
+        assert(ret_port);
+        assert(ret_server_name);
+
+        r = sd_bus_message_enter_container(message, 'r', extended ? "iayqs" : "iay");
+        if (r <= 0)
+                return r;
+
+        r = bus_message_read_in_addr_auto(message, error, &family, &a);
+        if (r < 0)
+                return r;
+
+        if (!dns_server_address_valid(family, &a))
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid DNS server address");
+
+        if (extended) {
+                r = sd_bus_message_read(message, "q", &port);
+                if (r < 0)
+                        return r;
+
+                if (IN_SET(port, 53, 853))
+                        port = 0;
+
+                r = sd_bus_message_read(message, "s", &server_name);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_bus_message_exit_container(message);
+        if (r < 0)
+                return r;
+
+        *ret_family = family;
+        *ret_address = a;
+        *ret_port = port;
+        *ret_server_name = server_name;
+
+        return 1;
+}
+
+int bus_message_read_dns_servers(
+                        sd_bus_message *message,
+                        sd_bus_error *error,
+                        bool extended,
+                        struct in_addr_full ***ret_dns,
+                        size_t *ret_n_dns) {
+
+        struct in_addr_full **dns = NULL;
+        size_t n = 0, allocated = 0;
+        int r;
+
+        assert(message);
+        assert(ret_dns);
+        assert(ret_n_dns);
+
+        r = sd_bus_message_enter_container(message, 'a', extended ? "(iayqs)" : "(iay)");
+        if (r < 0)
+                return r;
+
+        for (;;) {
+                const char *server_name;
+                union in_addr_union a;
+                uint16_t port;
+                int family;
+
+                r = bus_message_read_dns_one(message, error, extended, &family, &a, &port, &server_name);
+                if (r < 0)
+                        goto clear;
+                if (r == 0)
+                        break;
+
+                if (!GREEDY_REALLOC(dns, allocated, n+1)) {
+                        r = -ENOMEM;
+                        goto clear;
+                }
+
+                r = in_addr_full_new(family, &a, port, 0, server_name, dns + n);
+                if (r < 0)
+                        goto clear;
+
+                n++;
+        }
+
+        *ret_dns = TAKE_PTR(dns);
+        *ret_n_dns = n;
+        return 0;
+
+clear:
+        for (size_t i = 0; i < n; i++)
+                in_addr_full_free(dns[i]);
+        free(dns);
+
+        return r;
+}
diff --git a/src/shared/bus-message-util.h b/src/shared/bus-message-util.h
index 79bef325e3..90b78f415f 100644
--- a/src/shared/bus-message-util.h
+++ b/src/shared/bus-message-util.h
@@ -4,6 +4,14 @@
 #include "sd-bus.h"
 
 #include "in-addr-util.h"
+#include "socket-netlink.h"
 
 int bus_message_read_family(sd_bus_message *message, sd_bus_error *error, int *ret);
 int bus_message_read_in_addr_auto(sd_bus_message *message, sd_bus_error *error, int *ret_family, union in_addr_union *ret_addr);
+
+int bus_message_read_dns_servers(
+                        sd_bus_message *message,
+                        sd_bus_error *error,
+                        bool extended,
+                        struct in_addr_full ***ret_dns,
+                        size_t *ret_n_dns);