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authorLi RongQing <roy.qing.li@gmail.com>2015-10-15 16:54:36 +0800
committerDavid S. Miller <davem@davemloft.net>2015-10-18 19:23:52 -0700
commit26fb342c734061859fec1bd9e987bb6b78061ef0 (patch)
tree8e292c4de0611ef24b1e7ac70115c2e70cc5a1f7 /net/ipv4/ipconfig.c
parentMerge branch 'mlxsw-spectrum' (diff)
downloadlinux-dev-26fb342c734061859fec1bd9e987bb6b78061ef0.tar.xz
linux-dev-26fb342c734061859fec1bd9e987bb6b78061ef0.zip
ipconfig: send Client-identifier in DHCP requests
A dhcp server may provide parameters to a client from a pool of IP addresses and using a shared rootfs, or provide a specific set of parameters for a specific client, usually using the MAC address to identify each client individually. The dhcp protocol also specifies a client-id field which can be used to determine the correct parameters to supply when no MAC address is available. There is currently no way to tell the kernel to supply a specific client-id, only the userspace dhcp clients support this feature, but this can not be used when the network is needed before userspace is available such as when the root filesystem is on NFS. This patch is to be able to do something like "ip=dhcp,client_id_type, client_id_value", as a kernel parameter to enable the kernel to identify itself to the server. Signed-off-by: Li RongQing <roy.qing.li@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ipconfig.c')
-rw-r--r--net/ipv4/ipconfig.c32
1 files changed, 31 insertions, 1 deletions
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index ed4ef09c2136..0bc7412d9e14 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -146,6 +146,10 @@ u8 root_server_path[256] = { 0, }; /* Path to mount as root */
/* vendor class identifier */
static char vendor_class_identifier[253] __initdata;
+#if defined(CONFIG_IP_PNP_DHCP)
+static char dhcp_client_identifier[253] __initdata;
+#endif
+
/* Persistent data: */
static int ic_proto_used; /* Protocol used, if any */
@@ -728,6 +732,16 @@ ic_dhcp_init_options(u8 *options)
memcpy(e, vendor_class_identifier, len);
e += len;
}
+ len = strlen(dhcp_client_identifier + 1);
+ /* the minimum length of identifier is 2, include 1 byte type,
+ * and can not be larger than the length of options
+ */
+ if (len >= 1 && len < 312 - (e - options) - 1) {
+ *e++ = 61;
+ *e++ = len + 1;
+ memcpy(e, dhcp_client_identifier, len + 1);
+ e += len + 1;
+ }
}
*e++ = 255; /* End of the list */
@@ -1557,8 +1571,24 @@ static int __init ic_proto_name(char *name)
return 0;
}
#ifdef CONFIG_IP_PNP_DHCP
- else if (!strcmp(name, "dhcp")) {
+ else if (!strncmp(name, "dhcp", 4)) {
+ char *client_id;
+
ic_proto_enabled &= ~IC_RARP;
+ client_id = strstr(name, "dhcp,");
+ if (client_id) {
+ char *v;
+
+ client_id = client_id + 5;
+ v = strchr(client_id, ',');
+ if (!v)
+ return 1;
+ *v = 0;
+ if (kstrtou8(client_id, 0, dhcp_client_identifier))
+ DBG("DHCP: Invalid client identifier type\n");
+ strncpy(dhcp_client_identifier + 1, v + 1, 251);
+ *v = ',';
+ }
return 1;
}
#endif