libnet_build_igmp reserved field was mistakenly called 'code'

Looks like error occurred because function was a copy of
libnet_build_icmp().

3 files changed, 9 insertions, 7 deletions

diff --git a/libnet/include/libnet/libnet-functions.h b/libnet/include/libnet/libnet-functions.h
index 7cc3060..49a968f 100644
--- a/libnet/include/libnet/libnet-functions.h
+++ b/libnet/include/libnet/libnet-functions.h
@@ -797,7 +797,7 @@ uint8_t *payload, uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag);
 /**
  * Builds an RFC 1112 Internet Group Memebership Protocol (IGMP) header.
  * @param type packet type
- * @param code packet code (should be 0)
+ * @param reserved (should be 0 for IGMPv1)
  * @param sum checksum (0 for libnet to autofill)
  * @param ip IPv4 address (in standard/network byte order)
  * @param payload optional payload or NULL
@@ -805,9 +805,11 @@ uint8_t *payload, uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag);
  * @param l pointer to a libnet context
  * @param ptag protocol tag to modify an existing header, 0 to build a new one
  * @return protocol tag value on success, -1 on error
+ * 
+ * @note 'reserved' was previously called 'code', which it is not, in any IGMP version.
  */
 libnet_ptag_t
-libnet_build_igmp(uint8_t type, uint8_t code, uint16_t sum, uint32_t ip,
+libnet_build_igmp(uint8_t type, uint8_t reserved, uint16_t sum, uint32_t ip,
 const uint8_t* payload, uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag);
 
 /**
diff --git a/libnet/include/libnet/libnet-headers.h b/libnet/include/libnet/libnet-headers.h
index 11065c7..b126e39 100644
--- a/libnet/include/libnet/libnet-headers.h
+++ b/libnet/include/libnet/libnet-headers.h
@@ -1062,7 +1062,7 @@ struct libnet_igmp_hdr
 #ifndef IGMP_LEAVE_GROUP
 #define IGMP_LEAVE_GROUP                0x17    /* Leave-group message */
 #endif
-    uint8_t igmp_code;       /* IGMP code */
+    uint8_t igmp_code;       /* IGMP reserved field (0), mistakenly called 'code' in early libnet versions */
     uint16_t igmp_sum;       /* IGMP checksum */
     struct in_addr igmp_group;/* IGMP host IP */
 };
diff --git a/libnet/src/libnet_build_igmp.c b/libnet/src/libnet_build_igmp.c
index 9dd5bc6..70ac10d 100644
--- a/libnet/src/libnet_build_igmp.c
+++ b/libnet/src/libnet_build_igmp.c
@@ -40,7 +40,7 @@
 #endif
 
 libnet_ptag_t
-libnet_build_igmp(uint8_t type, uint8_t code, uint16_t sum, uint32_t ip,
+libnet_build_igmp(uint8_t type, uint8_t reserved, uint16_t sum, uint32_t ip,
 const uint8_t *payload, uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag)
 {
     uint32_t n, h;
@@ -66,9 +66,9 @@ const uint8_t *payload, uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag)
     }
 
     memset(&igmp_hdr, 0, sizeof(igmp_hdr));
-    igmp_hdr.igmp_type         = type;    /* packet type */
-    igmp_hdr.igmp_code         = code;    /* packet code */
-    igmp_hdr.igmp_sum          = (sum ? htons(sum) : 0);  /* packet checksum */
+    igmp_hdr.igmp_type         = type;
+    igmp_hdr.igmp_code         = reserved;
+    igmp_hdr.igmp_sum          = (sum ? htons(sum) : 0);
     igmp_hdr.igmp_group.s_addr = ip;
 
     n = libnet_pblock_append(l, p, (uint8_t *)&igmp_hdr, LIBNET_IGMP_H);