slirp: Add domain-search option to slirp's DHCP server

This patch will allow the user to include the domain-search option in
replies from the built-in DHCP server. The domain suffixes can be
specified by adding dnssearch= entries to the "-net user" parameter.

[Jan: tiny style adjustments]

Signed-off-by: Klaus Stengel <Klaus.Stengel@asamnet.de>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

1 files changed, 32 insertions, 3 deletions

diff --git a/net/slirp.c b/net/slirp.c
index bf86a44..afb52c3 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -136,7 +136,7 @@ static int net_slirp_init(NetClientState *peer, const char *model,
                           const char *vhostname, const char *tftp_export,
                           const char *bootfile, const char *vdhcp_start,
                           const char *vnameserver, const char *smb_export,
-                          const char *vsmbserver)
+                          const char *vsmbserver, const char **dnssearch)
 {
     /* default settings according to historic slirp */
     struct in_addr net  = { .s_addr = htonl(0x0a000200) }; /* 10.0.2.0 */
@@ -242,7 +242,7 @@ static int net_slirp_init(NetClientState *peer, const char *model,
     s = DO_UPCAST(SlirpState, nc, nc);
 
     s->slirp = slirp_init(restricted, net, mask, host, vhostname,
-                          tftp_export, bootfile, dhcp, dns, s);
+                          tftp_export, bootfile, dhcp, dns, dnssearch, s);
     QTAILQ_INSERT_TAIL(&slirp_stacks, s, entry);
 
     for (config = slirp_configs; config; config = config->next) {
@@ -699,6 +699,31 @@ net_init_slirp_configs(const StringList *fwd, int flags)
     }
 }
 
+static const char **slirp_dnssearch(const StringList *dnsname)
+{
+    const StringList *c = dnsname;
+    size_t i = 0, num_opts = 0;
+    const char **ret;
+
+    while (c) {
+        num_opts++;
+        c = c->next;
+    }
+
+    if (num_opts == 0) {
+        return NULL;
+    }
+
+    ret = g_malloc((num_opts + 1) * sizeof(*ret));
+    c = dnsname;
+    while (c) {
+        ret[i++] = c->value->str;
+        c = c->next;
+    }
+    ret[i] = NULL;
+    return ret;
+}
+
 int net_init_slirp(const NetClientOptions *opts, const char *name,
                    NetClientState *peer)
 {
@@ -706,6 +731,7 @@ int net_init_slirp(const NetClientOptions *opts, const char *name,
     char *vnet;
     int ret;
     const NetdevUserOptions *user;
+    const char **dnssearch;
 
     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_USER);
     user = opts->user;
@@ -714,6 +740,8 @@ int net_init_slirp(const NetClientOptions *opts, const char *name,
            user->has_ip  ? g_strdup_printf("%s/24", user->ip) :
            NULL;
 
+    dnssearch = slirp_dnssearch(user->dnssearch);
+
     /* all optional fields are initialized to "all bits zero" */
 
     net_init_slirp_configs(user->hostfwd, SLIRP_CFG_HOSTFWD);
@@ -722,7 +750,7 @@ int net_init_slirp(const NetClientOptions *opts, const char *name,
     ret = net_slirp_init(peer, "user", name, user->q_restrict, vnet,
                          user->host, user->hostname, user->tftp,
                          user->bootfile, user->dhcpstart, user->dns, user->smb,
-                         user->smbserver);
+                         user->smbserver, dnssearch);
 
     while (slirp_configs) {
         config = slirp_configs;
@@ -731,6 +759,7 @@ int net_init_slirp(const NetClientOptions *opts, const char *name,
     }
 
     g_free(vnet);
+    g_free(dnssearch);
 
     return ret;
 }