[DCCP]: Miscellaneous code tidy-ups
This patch does not change code; it performs some trivial clean/tidy-ups:
* removal of a `debug_prefix' string in favour of the
already existing dccp_role(sk)
* add documentation of structures and constants
* separated out the cases for invalid packets (step 1
of the packet validation)
* removing duplicate statements
* combining declaration & initialisation
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 61c0901..34d6d19 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -518,7 +518,7 @@
sizeof(struct dccp_hdr_reset);
struct sk_buff *skb;
struct dst_entry *dst;
- u64 seqno;
+ u64 seqno = 0;
/* Never send a reset in response to a reset. */
if (rxdh->dccph_type == DCCP_PKT_RESET)
@@ -552,13 +552,11 @@
DCCP_SKB_CB(rxskb)->dccpd_reset_code;
/* See "8.3.1. Abnormal Termination" in RFC 4340 */
- seqno = 0;
if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
dccp_hdr_set_seq(dh, seqno);
- dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
- DCCP_SKB_CB(rxskb)->dccpd_seq);
+ dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), DCCP_SKB_CB(rxskb)->dccpd_seq);
dccp_csum_outgoing(skb);
dh->dccph_checksum = dccp_v4_csum_finish(skb, rxskb->nh.iph->saddr,
@@ -734,6 +732,11 @@
EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
+/**
+ * dccp_invalid_packet - check for malformed packets
+ * Implements RFC 4340, 8.5: Step 1: Check header basics
+ * Packets that fail these checks are ignored and do not receive Resets.
+ */
int dccp_invalid_packet(struct sk_buff *skb)
{
const struct dccp_hdr *dh;
@@ -742,6 +745,7 @@
if (skb->pkt_type != PACKET_HOST)
return 1;
+ /* If the packet is shorter than 12 bytes, drop packet and return */
if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
return 1;
@@ -749,42 +753,37 @@
dh = dccp_hdr(skb);
- /* If the packet type is not understood, drop packet and return */
+ /* If P.type is not understood, drop packet and return */
if (dh->dccph_type >= DCCP_PKT_INVALID) {
LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
return 1;
}
/*
- * If P.Data Offset is too small for packet type, or too large for
- * packet, drop packet and return
+ * If P.Data Offset is too small for packet type, drop packet and return
*/
if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
- "too small 1\n",
- dh->dccph_doff);
+ "too small\n", dh->dccph_doff);
return 1;
}
-
+ /*
+ * If P.Data Offset is too too large for packet, drop packet and return
+ */
if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
- "too small 2\n",
- dh->dccph_doff);
+ "too large\n", dh->dccph_doff);
return 1;
}
- dh = dccp_hdr(skb);
-
/*
* If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
* has short sequence numbers), drop packet and return
*/
- if (dh->dccph_x == 0 &&
- dh->dccph_type != DCCP_PKT_DATA &&
- dh->dccph_type != DCCP_PKT_ACK &&
- dh->dccph_type != DCCP_PKT_DATAACK) {
- LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
- "nor DataAck and P.X == 0\n",
+ if (dh->dccph_type >= DCCP_PKT_DATA &&
+ dh->dccph_type <= DCCP_PKT_DATAACK && dh->dccph_x == 0) {
+ LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data||Ack||"
+ "DataAck, while P.X == 0\n",
dccp_packet_name(dh->dccph_type));
return 1;
}