[DCCP]: Factor out common code for generating Resets
This factors code common to dccp_v{4,6}_ctl_send_reset into a separate function,
and adds support for filling in the Data 1 ... Data 3 fields from RFC 4340,
5.6.
It is useful to have this separate, since the following Reset codes will always
be generated from the control socket rather than via dccp_send_reset:
* Code 3, "No Connection", cf. 8.3.1;
* Code 4, "Packet Error" (identification for Data 1 added);
* Code 5, "Option Error" (identification for Data 1..3 added, will be used
later);
* Code 6, "Mandatory Error" (same as Option Error);
* Code 7, "Connection Refused" (what on Earth is the difference to "No
Connection"?);
* Code 8, "Bad Service Code";
* Code 9, "Too Busy";
* Code 10, "Bad Init Cookie" (not used).
Code 0 is not recommended by the RFC, the following codes would be used in
dccp_send_reset() instead, since they all relate to an established DCCP
connection:
* Code 1, "Closed";
* Code 2, "Aborted";
* Code 11, "Aggression Penalty" (12.3).
Signed-off-by: Gerrit Renker <[EMAIL PROTECTED]>
---
net/dccp/dccp.h |2 ++
net/dccp/ipv4.c | 38 +-
net/dccp/ipv6.c | 39 ++-
net/dccp/output.c | 52
4 files changed, 65 insertions(+), 66 deletions(-)
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -298,6 +298,8 @@ extern unsigned int dccp_poll(struct fil
extern intdccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
int addr_len);
+extern struct sk_buff *
+ dccp_ctl_make_reset(struct socket *ctl, struct sk_buff *skb);
extern intdccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
extern void dccp_send_close(struct sock *sk, const int active);
extern intdccp_invalid_packet(struct sk_buff *skb);
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -331,6 +331,58 @@ struct sk_buff *dccp_make_response(struc
EXPORT_SYMBOL_GPL(dccp_make_response);
+/* answer offending packet in @rcv_skb with Reset from control socket @ctl */
+struct sk_buff *dccp_ctl_make_reset(struct socket *ctl, struct sk_buff
*rcv_skb)
+{
+ struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh;
+ struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb);
+ const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
+ sizeof(struct dccp_hdr_ext) +
+ sizeof(struct dccp_hdr_reset);
+ struct dccp_hdr_reset *dhr;
+ struct sk_buff *skb;
+
+ skb = alloc_skb(ctl->sk->sk_prot->max_header, GFP_ATOMIC);
+ if (skb == NULL)
+ return NULL;
+
+ skb_reserve(skb, ctl->sk->sk_prot->max_header);
+
+ /* Swap the send and the receive. */
+ dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
+ dh->dccph_type = DCCP_PKT_RESET;
+ dh->dccph_sport = rxdh->dccph_dport;
+ dh->dccph_dport = rxdh->dccph_sport;
+ dh->dccph_doff = dccp_hdr_reset_len / 4;
+ dh->dccph_x = 1;
+
+ dhr = dccp_hdr_reset(skb);
+ dhr->dccph_reset_code = dcb->dccpd_reset_code;
+
+ switch (dcb->dccpd_reset_code) {
+ case DCCP_RESET_CODE_PACKET_ERROR:
+ dhr->dccph_reset_data[0] = rxdh->dccph_type;
+ break;
+ case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */
+ case DCCP_RESET_CODE_MANDATORY_ERROR:
+ memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3);
+ break;
+ }
+ /*
+* From RFC 4340, 8.3.1:
+* If P.ackno exists, set R.seqno := P.ackno + 1.
+* Else set R.seqno := 0.
+*/
+ if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
+ dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1));
+ dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq);
+
+ dccp_csum_outgoing(skb);
+ return skb;
+}
+
+EXPORT_SYMBOL_GPL(dccp_ctl_make_reset);
+
/* send Reset on established socket, to close or abort the connection */
int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
{
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -512,17 +512,12 @@ out:
static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
{
int err;
- struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
const struct iphdr *rxiph;
- const int dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
- sizeof(struct dccp_hdr_ext) +
- sizeof(struct dccp_hdr_reset);
struct sk_buff *skb;
struct dst_entry *dst;
- u64 seqno = 0;
/* Never send a reset in response to a reset. */
- if (rxdh->dccph_type == DCCP_PKT_RESET)
+ if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
return;
if (((struct rtable *)rxskb->dst)->rt_type != RTN_
