slirp: Add domain-search option to slirp's DHCP server (63d2960b) · Commits · SUMMER2020 / students / proj-2021291

net/slirp.c

+32 −3

Original line number	Diff line number	Diff line
		@@ -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;
		}

qapi-schema.json

+4 −0

Original line number	Diff line number	Diff line
		@@ -2404,6 +2404,9 @@
		#
		# @dns: #optional guest-visible address of the virtual nameserver
		#
		# @dnssearch: #optional list of DNS suffixes to search, passed as DHCP option
		# to the guest
		#
		# @smb: #optional root directory of the built-in SMB server
		#
		# @smbserver: #optional IP address of the built-in SMB server
		@@ -2426,6 +2429,7 @@
		'*bootfile': 'str',
		'*dhcpstart': 'str',
		'*dns': 'str',
		'*dnssearch': ['String'],
		'*smb': 'str',
		'*smbserver': 'str',
		'*hostfwd': ['String'],

qemu-options.hx

+15 −3

Original line number	Diff line number	Diff line
		@@ -1318,8 +1318,8 @@ DEF("net", HAS_ARG, QEMU_OPTION_net,
		" create a new Network Interface Card and connect it to VLAN 'n'\n"
		#ifdef CONFIG_SLIRP
		"-net user[,vlan=n][,name=str][,net=addr[/mask]][,host=addr][,restrict=on\|off]\n"
		" [,hostname=host][,dhcpstart=addr][,dns=addr][,tftp=dir][,bootfile=f]\n"
		" [,hostfwd=rule][,guestfwd=rule]"
		" [,hostname=host][,dhcpstart=addr][,dns=addr][,dnssearch=domain][,tftp=dir]\n"
		" [,bootfile=f][,hostfwd=rule][,guestfwd=rule]"
		#ifndef _WIN32
		"[,smb=dir[,smbserver=addr]]\n"
		#endif
		@@ -1428,7 +1428,7 @@ able to contact the host and no guest IP packets will be routed over the host
		to the outside. This option does not affect any explicitly set forwarding rules.

		@item hostname=@var{name}
		Specifies the client hostname reported by the builtin DHCP server.
		Specifies the client hostname reported by the built-in DHCP server.

		@item dhcpstart=@var{addr}
		Specify the first of the 16 IPs the built-in DHCP server can assign. Default
		@@ -1439,6 +1439,18 @@ Specify the guest-visible address of the virtual nameserver. The address must
		be different from the host address. Default is the 3rd IP in the guest network,
		i.e. x.x.x.3.

		@item dnssearch=@var{domain}
		Provides an entry for the domain-search list sent by the built-in
		DHCP server. More than one domain suffix can be transmitted by specifying
		this option multiple times. If supported, this will cause the guest to
		automatically try to append the given domain suffix(es) in case a domain name
		can not be resolved.

		Example:
		@example
		qemu -net user,dnssearch=mgmt.example.org,dnssearch=example.org [...]
		@end example

		@item tftp=@var{dir}
		When using the user mode network stack, activate a built-in TFTP
		server. The files in @var{dir} will be exposed as the root of a TFTP server.

slirp/Makefile.objs

+1 −1

Original line number	Diff line number	Diff line
		common-obj-y = cksum.o if.o ip_icmp.o ip_input.o ip_output.o
		common-obj-y = cksum.o if.o ip_icmp.o ip_input.o ip_output.o dnssearch.o
		common-obj-y += slirp.o mbuf.o misc.o sbuf.o socket.o tcp_input.o tcp_output.o
		common-obj-y += tcp_subr.o tcp_timer.o udp.o bootp.o tftp.o arp_table.o

slirp/bootp.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -287,6 +287,18 @@ static void bootp_reply(Slirp slirp, const struct bootp_t bp)
		memcpy(q, slirp->client_hostname, val);
		q += val;
		}

		if (slirp->vdnssearch) {
		size_t spaceleft = sizeof(rbp->bp_vend) - (q - rbp->bp_vend);
		val = slirp->vdnssearch_len;
		if (val + 1 > spaceleft) {
		g_warning("DHCP packet size exceeded, "
		"omitting domain-search option.");
		} else {
		memcpy(q, slirp->vdnssearch, val);
		q += val;
		}
		}
		} else {
		static const char nak_msg[] = "requested address not available";