diff options
Diffstat (limited to 'net/dccp/output.c')
| -rw-r--r-- | net/dccp/output.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/net/dccp/output.c b/net/dccp/output.c index f4bde205620..6a334ed5e9d 100644 --- a/net/dccp/output.c +++ b/net/dccp/output.c @@ -327,6 +327,58 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, 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) { |