[PATCH 05/16] kvm tools: Get domain name and nameserver from host

[Asias He <asias.hejun@xxxxxxxxx>]

This patch get domain name and nameserver information from host config
file /etc/resolv.conf.

Guest can obtain DNS information through DHCP.

Signed-off-by: Asias He <asias.hejun@xxxxxxxxx>
---
 tools/kvm/include/kvm/uip.h |    6 ++++++
 tools/kvm/net/uip/dhcp.c    |   34 ++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/tools/kvm/include/kvm/uip.h b/tools/kvm/include/kvm/uip.h
index 6534c7f..e645d3f 100644
--- a/tools/kvm/include/kvm/uip.h
+++ b/tools/kvm/include/kvm/uip.h
@@ -42,6 +42,8 @@
 #define UIP_DHCP_OFFER			2
 #define UIP_DHCP_REQUEST		3
 #define UIP_DHCP_ACK			5
+#define UIP_DHCP_MAX_DNS_SERVER_NR	3
+#define UIP_DHCP_MAX_DOMAIN_NAME_LEN	256
 #define UIP_DHCP_TAG_MSG_TYPE		53
 #define UIP_DHCP_TAG_MSG_TYPE_LEN	1
 /*
@@ -178,6 +180,8 @@ struct uip_info {
 	int buf_free_nr;
 	int buf_used_nr;
 	u32 host_ip;
+	u32 dns_ip[UIP_DHCP_MAX_DNS_SERVER_NR];
+	char *domain_name;
 	u32 buf_nr;
 };
 
@@ -327,4 +331,6 @@ struct uip_buf *uip_buf_clone(struct uip_tx_arg *arg);
 
 int uip_udp_make_pkg(struct uip_info *info, struct uip_udp_socket *sk, struct uip_buf *buf, u8 *payload, int payload_len);
 bool uip_udp_is_dhcp(struct uip_udp *udp);
+
+int uip_dhcp_get_dns(struct uip_info *info);
 #endif /* KVM__UIP_H */
diff --git a/tools/kvm/net/uip/dhcp.c b/tools/kvm/net/uip/dhcp.c
index 0a6293a..9321cdc 100644
--- a/tools/kvm/net/uip/dhcp.c
+++ b/tools/kvm/net/uip/dhcp.c
@@ -1,5 +1,7 @@
 #include "kvm/uip.h"
 
+#include <arpa/inet.h>
+
 static inline bool uip_dhcp_is_discovery(struct uip_dhcp *dhcp)
 {
 	return (dhcp->option[2] == UIP_DHCP_DISCOVER &&
@@ -29,3 +31,35 @@ bool uip_udp_is_dhcp(struct uip_udp *udp)
 
 	return true;
 }
+
+int uip_dhcp_get_dns(struct uip_info *info)
+{
+	char key[256], val[256];
+	struct in_addr addr;
+	int ret = -1;
+	int n = 0;
+	FILE *fp;
+	u32 ip;
+
+	fp = fopen("/etc/resolv.conf", "r");
+	if (!fp)
+		goto out;
+
+	while (!feof(fp)) {
+		fscanf(fp, "%s %s\n", key, val);
+		if (strncmp("domain", key, 6) == 0)
+			info->domain_name = strndup(val, UIP_DHCP_MAX_DOMAIN_NAME_LEN);
+		else if (strncmp("nameserver", key, 10) == 0) {
+			if (!inet_aton(val, &addr))
+				continue;
+			ip = ntohl(addr.s_addr);
+			if (n < UIP_DHCP_MAX_DNS_SERVER_NR)
+				info->dns_ip[n++] = ip;
+			ret = 0;
+		}
+	}
+
+out:
+	fclose(fp);
+	return ret;
+}
-- 
1.7.5.4

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