[SLOF] [PATCH 7/7] net-snk: Get rid of junk at the end of sent DHCPv6 packets

[Thomas Huth]

Wireshark reports bad FCS values and trailing zeros for SLOF's
DHCPv6 packets. This happens due to two bugs. First, the length
given to send_ipv6() contained sizeof(struct ethhdr) - but
adding that length is the responsibility of the send_ipv6()
function itself, the upper layers must not add this length yet.
Second, struct option_request was defined with 5 options, but
the code only uses 3 options instead. So when the code uses
sizeof(struct dhcp_message_header) (which contains the struct
option_request), there were additional unused bytes appended
to the message.

Signed-off-by: Thomas Huth <thuth at redhat.com>
---
 clients/net-snk/app/netlib/dhcpv6.c | 8 +++-----
 clients/net-snk/app/netlib/dhcpv6.h | 4 +++-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/clients/net-snk/app/netlib/dhcpv6.c b/clients/net-snk/app/netlib/dhcpv6.c
index 05e9fcd..1a4ce6d 100644
--- a/clients/net-snk/app/netlib/dhcpv6.c
+++ b/clients/net-snk/app/netlib/dhcpv6.c
@@ -70,16 +70,14 @@ send_info_request(int fd)
 	dhcph->option.el_time.length = 2;
 	dhcph->option.el_time.time = 0x190; /* 4000 ms */
 	dhcph->option.option_request_option.code = DHCPV6_OPTION_ORO;
-	dhcph->option.option_request_option.length= 6;
+	dhcph->option.option_request_option.length= DHCPV6_OPTREQUEST_NUMOPTS * 2;
 	dhcph->option.option_request_option.option_code[0] = DHCPV6_OPTION_DNS_SERVERS;
 	dhcph->option.option_request_option.option_code[1] = DHCPV6_OPTION_DOMAIN_LIST;
 	dhcph->option.option_request_option.option_code[2] = DHCPV6_OPTION_BOOT_URL;
 
-
 	send_ipv6(fd, ether_packet + sizeof(struct ethhdr),
-	         sizeof(struct ethhdr)+ sizeof(struct ip6hdr)
-		 + sizeof(struct udphdr)
-	         + sizeof( struct dhcp_message_header) );
+		  sizeof(struct ip6hdr) + sizeof(struct udphdr)
+		  + sizeof(struct dhcp_message_header));
 }
 
 static int32_t
diff --git a/clients/net-snk/app/netlib/dhcpv6.h b/clients/net-snk/app/netlib/dhcpv6.h
index dcda9b1..404706e 100644
--- a/clients/net-snk/app/netlib/dhcpv6.h
+++ b/clients/net-snk/app/netlib/dhcpv6.h
@@ -103,6 +103,8 @@ struct server_identifier {
 	uint8_t mac[6];
 };
 
+#define DHCPV6_OPTREQUEST_NUMOPTS 3
+
 struct dhcp_info_request {
 	struct client_identifier client_id;
 	struct elapsed_time {
@@ -113,7 +115,7 @@ struct dhcp_info_request {
 	struct option_request {
 		uint16_t code;
 		uint16_t length;
-		uint16_t option_code[5];
+		uint16_t option_code[DHCPV6_OPTREQUEST_NUMOPTS];
 	} option_request_option;
 };
 
-- 
1.8.3.1