udhcpc: in comments, explain the kind of raw socket we create

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index ee19f5578..bdb1e2b9b 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -979,6 +979,10 @@ static int udhcp_raw_socket(int ifindex)
         log1("Opening raw socket on ifindex %d", ifindex); //log2?
 
         fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
+        /* ^^^^^
+         * SOCK_DGRAM: remove link-layer headers on input (SOCK_RAW keeps them)
+         * ETH_P_IP: want to receive only packets with IPv4 eth type
+         */
         log1("Got raw socket fd"); //log2?
 
         sock.sll_family = AF_PACKET;
@@ -1005,8 +1009,6 @@ static int udhcp_raw_socket(int ifindex)
                  *
                  * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
                  * License: GPL v2.
-                 *
-                 * TODO: make conditional?
                  */
                 static const struct sock_filter filter_instr[] = {
                         /* load 9th byte (protocol) */