[klibc] ipconfig: Write $DOMAINSEARCH as domain-search

This patch requests domain-search option to DHCP servers, and parses
domain-search option value in DHCP ACK packet when ipconfig uses DHCP.
This patch writes $DOMAINSEARCH as the value to /tmp/net-$DEVICE.conf file.

> ipconfig: ignores dhcp options
> http://bugs.debian.org/627166
This Debian Bug report requests the option value.

The format of $DOMAINSEARCH is domain name list which is separated with ' '.
For example, $DOMAINSEARCH is either 'foo1.bar. foo2.bar.', 'foo.', or ''.

Signed-off-by: KUMAAN <9maaan@gmail.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: maximilian attems <max@stro.at>

5 files changed, 253 insertions, 3 deletions

diff --git a/usr/kinit/ipconfig/bootp_packet.h b/usr/kinit/ipconfig/bootp_packet.h
index 6016e5f3a90240..1ef505e4075e72 100644
--- a/usr/kinit/ipconfig/bootp_packet.h
+++ b/usr/kinit/ipconfig/bootp_packet.h
@@ -28,4 +28,14 @@ struct bootp_hdr {
 	/* 312 bytes of extensions */
 };
 
+/*
+ * memory size of BOOTP Vendor Extensions/DHCP Options for receiving
+ *
+ * generic_ether_mtu:1500, min_sizeof(ip_hdr):20, sizeof(udp_hdr):8
+ *
+ * #define BOOTP_EXTS_SIZE	(1500 - 20 - 8 - sizeof(struct bootp_hdr))
+ */
+/* larger size for backward compatibility of ipconfig */
+#define BOOTP_EXTS_SIZE	1500
+
 #endif /* BOOTP_PACKET_H */
diff --git a/usr/kinit/ipconfig/bootp_proto.c b/usr/kinit/ipconfig/bootp_proto.c
index e3d50e32501068..150ebfa7952b81 100644
--- a/usr/kinit/ipconfig/bootp_proto.c
+++ b/usr/kinit/ipconfig/bootp_proto.c
@@ -56,11 +56,226 @@ int bootp_send_request(struct netdev *dev)
 }
 
 /*
+ * DESCRIPTION
+ *  bootp_ext119_decode() decodes Domain Search Option data.
+ *  The decoded string is separated with ' '.
+ *  For example, it is either "foo.bar.baz. bar.baz.", "foo.bar.", or "foo.".
+ *
+ * ARGUMENTS
+ *  const uint8_t *ext
+ *   *ext is a pointer to a DHCP Domain Search Option data. *ext does not
+ *   include a tag(code) octet and a length octet in DHCP options.
+ *   For example, if *ext is {3, 'f', 'o', 'o', 0}, this function returns
+ *   a pointer to a "foo." string.
+ *
+ *  int16_t ext_size
+ *   ext_size is the memory size of *ext. For example,
+ *   if *ext is {3, 'f', 'o', 'o', 0}, ext_size must be 5.
+ *
+ *  uint8_t *tmp
+ *   *tmp is a pointer to a temporary memory space for decoding.
+ *   The memory size must be equal to or more than ext_size.
+ *   'memset(tmp, 0, sizeof(tmp));' is not required, but values in *tmp
+ *   are changed in decoding process.
+ *
+ * RETURN VALUE
+ *  if OK, a pointer to a decoded string malloc-ed
+ *  else , NULL
+ *
+ * SEE ALSO RFC3397
+ */
+static char *bootp_ext119_decode(const void *ext, int16_t ext_size, void *tmp)
+{
+	uint8_t *u8ext;
+	int_fast32_t i;
+	int_fast32_t decoded_size;
+	int_fast8_t currentdomain_is_singledot;
+
+	/* only for validating *ext */
+	uint8_t *is_pointee;
+	int_fast32_t is_pointee_size;
+
+	/* only for structing a decoded string */
+	char *decoded_str;
+	int_fast32_t dst_i;
+
+	if (ext == NULL || ext_size <= 0 || tmp == NULL)
+		return NULL;
+
+	u8ext = (uint8_t *)ext;
+	is_pointee = tmp;
+	memset(is_pointee, 0, (size_t)ext_size);
+	is_pointee_size = 0;
+
+	/*
+	 * validate the format of *ext and
+	 * calculate the memory size for a decoded string
+	 */
+	i = 0;
+	decoded_size = 0;
+	currentdomain_is_singledot = 1;
+	while (1) {
+		if (i >= ext_size)
+			return NULL;
+
+		if (u8ext[i] == 0) {
+			/* Zero-ending */
+			if (currentdomain_is_singledot)
+				decoded_size++; /* for '.' */
+			decoded_size++; /* for ' ' or '\0' */
+			currentdomain_is_singledot = 1;
+			i++;
+			if (i == ext_size)
+				break;
+			is_pointee_size = i;
+		} else if (u8ext[i] < 0x40) {
+			/* Label(sub-domain string) */
+			int j;
+
+			/* loosely validate characters for domain names */
+			if (i + u8ext[i] >= ext_size)
+				return NULL;
+			for (j = i + 1; j <= i + u8ext[i]; j++)
+				if (!(u8ext[j] == '-' ||
+				     ('0' <= u8ext[j] && u8ext[j] <= '9') ||
+				     ('A' <= u8ext[j] && u8ext[j] <= 'Z') ||
+				     ('a' <= u8ext[j] && u8ext[j] <= 'z')))
+					return NULL;
+
+			is_pointee[i] = 1;
+			decoded_size += u8ext[i] + 1; /* for Label + '.' */
+			currentdomain_is_singledot = 0;
+			i += u8ext[i] + 1;
+		} else if (u8ext[i] < 0xc0)
+			return NULL;
+
+		else {
+			/* Compression-pointer (to a prior Label) */
+			int_fast32_t p;
+
+			if (i + 1 >= ext_size)
+				return NULL;
+
+			p = ((0x3f & u8ext[i]) << 8) + u8ext[i + 1];
+			if (!(p < is_pointee_size && is_pointee[p]))
+				return NULL;
+
+			while (1) {
+				/* u8ext[p] was validated */
+				if (u8ext[p] == 0) {
+					/* Zero-ending */
+					decoded_size++;
+					break;
+				} else if (u8ext[p] < 0x40) {
+					/* Label(sub-domain string) */
+					decoded_size += u8ext[p] + 1;
+					p += u8ext[p] + 1;
+				} else {
+					/* Compression-pointer */
+					p = ((0x3f & u8ext[p]) << 8)
+						+ u8ext[p + 1];
+				}
+			}
+
+			currentdomain_is_singledot = 1;
+			i += 2;
+			if (i == ext_size)
+				break;
+			is_pointee_size = i;
+		}
+	}
+
+
+	/*
+	 * construct a decoded string
+	 */
+	decoded_str = malloc(decoded_size);
+	if (decoded_str == NULL)
+		return NULL;
+
+	i = 0;
+	dst_i = 0;
+	currentdomain_is_singledot = 1;
+	while (1) {
+		if (u8ext[i] == 0) {
+			/* Zero-ending */
+			if (currentdomain_is_singledot) {
+				if (dst_i != 0)
+					dst_i++;
+				decoded_str[dst_i] = '.';
+			}
+			dst_i++;
+			decoded_str[dst_i] = ' ';
+
+			currentdomain_is_singledot = 1;
+			i++;
+			if (i == ext_size)
+				break;
+		} else if (u8ext[i] < 0x40) {
+			/* Label(sub-domain string) */
+			if (dst_i != 0)
+				dst_i++;
+			memcpy(&decoded_str[dst_i], &u8ext[i + 1],
+			       (size_t)u8ext[i]);
+			dst_i += u8ext[i];
+			decoded_str[dst_i] = '.';
+
+			currentdomain_is_singledot = 0;
+			i += u8ext[i] + 1;
+		} else {
+			/* Compression-pointer (to a prior Label) */
+			int_fast32_t p;
+
+			p = ((0x3f & u8ext[i]) << 8) + u8ext[i + 1];
+			while (1) {
+				if (u8ext[p] == 0) {
+					/* Zero-ending */
+					decoded_str[dst_i++] = '.';
+					decoded_str[dst_i] = ' ';
+					break;
+				} else if (u8ext[p] < 0x40) {
+					/* Label(sub-domain string) */
+					dst_i++;
+					memcpy(&decoded_str[dst_i],
+					       &u8ext[p + 1],
+					       (size_t)u8ext[p]);
+					dst_i += u8ext[p];
+					decoded_str[dst_i] = '.';
+
+					p += u8ext[p] + 1;
+				} else {
+					/* Compression-pointer */
+					p = ((0x3f & u8ext[p]) << 8)
+						+ u8ext[p + 1];
+				}
+			}
+
+			currentdomain_is_singledot = 1;
+			i += 2;
+			if (i == ext_size)
+				break;
+		}
+	}
+	decoded_str[dst_i] = '\0';
+#ifdef DEBUG
+	if (dst_i + 1 != decoded_size) {
+		dprintf("bug:%s():bottom: malloc(%ld), write(%ld)\n",
+			__func__, (long)decoded_size, (long)(dst_i + 1));
+		exit(1);
+	}
+#endif
+	return decoded_str;
+}
+
+/*
  * Parse a bootp reply packet
  */
 int bootp_parse(struct netdev *dev, struct bootp_hdr *hdr,
 		uint8_t *exts, int extlen)
 {
+	uint8_t ext119_buf[BOOTP_EXTS_SIZE];
+	int16_t ext119_len = 0;
+
 	dev->bootp.gateway	= hdr->giaddr;
 	dev->ip_addr		= hdr->yiaddr;
 	dev->ip_server		= hdr->siaddr;
@@ -143,11 +358,32 @@ int bootp_parse(struct netdev *dev, struct bootp_hdr *hdr,
 				if (len == 4 && !dev->ip_server)
 					memcpy(&dev->ip_server, ext, 4);
 				break;
+			case 119:	/* Domain Search Option */
+				if (ext119_len >= 0 &&
+				    ext119_len + len <= sizeof(ext119_buf)) {
+					memcpy(ext119_buf + ext119_len,
+					       ext, len);
+					ext119_len += len;
+				} else
+					ext119_len = -1;
+
+				break;
 			}
 
 			ext += len;
 		}
 	}
+	if (ext119_len > 0) {
+		char *ret;
+		uint8_t ext119_tmp[BOOTP_EXTS_SIZE];
+
+		ret = bootp_ext119_decode(ext119_buf, ext119_len, ext119_tmp);
+		if (ret != NULL) {
+			if (dev->domainsearch != NULL)
+				free(dev->domainsearch);
+			dev->domainsearch = ret;
+		}
+	}
 
 	/*
 	 * Got packet.
@@ -165,11 +401,11 @@ int bootp_parse(struct netdev *dev, struct bootp_hdr *hdr,
 int bootp_recv_reply(struct netdev *dev)
 {
 	struct bootp_hdr bootp;
-	uint8_t bootp_options[312];
+	uint8_t bootp_options[BOOTP_EXTS_SIZE];
 	struct iovec iov[] = {
 		/* [0] = ip + udp headers */
 		[1] = {&bootp, sizeof(struct bootp_hdr)},
-		[2] = {bootp_options, 312}
+		[2] = {bootp_options, sizeof(bootp_options)}
 	};
 	int ret;
 
diff --git a/usr/kinit/ipconfig/dhcp_proto.c b/usr/kinit/ipconfig/dhcp_proto.c
index 8ca2614072b16a..0c907e9466a842 100644
--- a/usr/kinit/ipconfig/dhcp_proto.c
+++ b/usr/kinit/ipconfig/dhcp_proto.c
@@ -25,6 +25,7 @@ static uint8_t dhcp_params[] = {
 	26,			/* interface mtu */
 	28,			/* broadcast addr */
 	40,			/* NIS domain name (why?) */
+	119,			/* Domain Search Option */
 };
 
 static uint8_t dhcp_discover_hdr[] = {
@@ -158,7 +159,7 @@ static int dhcp_parse(struct netdev *dev, struct bootp_hdr *hdr,
 static int dhcp_recv(struct netdev *dev)
 {
 	struct bootp_hdr bootp;
-	uint8_t dhcp_options[1500];
+	uint8_t dhcp_options[BOOTP_EXTS_SIZE];
 	struct iovec iov[] = {
 		/* [0] = ip + udp header */
 		[1] = {&bootp, sizeof(struct bootp_hdr)},
diff --git a/usr/kinit/ipconfig/main.c b/usr/kinit/ipconfig/main.c
index 148ccb66fa3b12..476384acbd04b4 100644
--- a/usr/kinit/ipconfig/main.c
+++ b/usr/kinit/ipconfig/main.c
@@ -176,6 +176,8 @@ static void dump_device_config(struct netdev *dev)
 		write_option(f, "UPTIME", buf21);
 		sprintf(buf21, "%u", (unsigned int)dev->dhcpleasetime);
 		write_option(f, "DHCPLEASETIME", buf21);
+		write_option(f, "DOMAINSEARCH", dev->domainsearch == NULL ?
+			     "" : dev->domainsearch);
 		fclose(f);
 	}
 }
diff --git a/usr/kinit/ipconfig/netdev.h b/usr/kinit/ipconfig/netdev.h
index f4198804e60cc2..cd853b6c078b41 100644
--- a/usr/kinit/ipconfig/netdev.h
+++ b/usr/kinit/ipconfig/netdev.h
@@ -43,6 +43,7 @@ struct netdev {
 	char nisdomainname[SYS_NMLN];	/* nis domain name      */
 	char bootpath[BPLEN];	/* boot path            */
 	char filename[FNLEN];   /* filename             */
+	char *domainsearch;	/* decoded, NULL or malloc-ed  */
 	long uptime;		/* when complete configuration */
 	struct netdev *next;	/* next configured i/f  */
 };