static int dccp_v4_send_response(struct sock *sk, struct request_sock *req, struct dst_entry *dst) { int err = -1; struct sk_buff *skb; /* First, grab a route. */ if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL) goto out; skb = dccp_make_response(sk, dst, req); if (skb != NULL) { const struct inet_request_sock *ireq = inet_rsk(req); struct dccp_hdr *dh = dccp_hdr(skb); dh->dccph_checksum = dccp_v4_checksum(skb, ireq->loc_addr, ireq->rmt_addr); memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr, ireq->rmt_addr, ireq->opt); if (err == NET_XMIT_CN) err = 0; } out: dst_release(dst); return err; }
static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk, struct sk_buff *skb) { struct rtable *rt; const struct iphdr *iph = ip_hdr(skb); struct flowi4 fl4 = { .flowi4_oif = inet_iif(skb), .daddr = iph->saddr, .saddr = iph->daddr, .flowi4_tos = RT_CONN_FLAGS(sk), .flowi4_proto = sk->sk_protocol, .fl4_sport = dccp_hdr(skb)->dccph_dport, .fl4_dport = dccp_hdr(skb)->dccph_sport, }; security_skb_classify_flow(skb, flowi4_to_flowi(&fl4)); rt = ip_route_output_flow(net, &fl4, sk); if (IS_ERR(rt)) { IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); return NULL; } return &rt->dst; } static int dccp_v4_send_response(const struct sock *sk, struct request_sock *req) { int err = -1; struct sk_buff *skb; struct dst_entry *dst; struct flowi4 fl4; dst = inet_csk_route_req(sk, &fl4, req); if (dst == NULL) goto out; skb = dccp_make_response(sk, dst, req); if (skb != NULL) { const struct inet_request_sock *ireq = inet_rsk(req); struct dccp_hdr *dh = dccp_hdr(skb); dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); rcu_read_lock(); err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, ireq->ir_rmt_addr, rcu_dereference(ireq->ireq_opt)); rcu_read_unlock(); err = net_xmit_eval(err); } out: dst_release(dst); return err; }
static void dccp_v4_reqsk_send_ack(struct sk_buff *rxskb, struct request_sock *req) { int err; struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh; const u32 dccp_hdr_ack_len = sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext) + sizeof(struct dccp_hdr_ack_bits); struct sk_buff *skb; if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL) return; skb = alloc_skb(dccp_v4_ctl_socket->sk->sk_prot->max_header, GFP_ATOMIC); if (skb == NULL) return; /* Reserve space for headers. */ skb_reserve(skb, dccp_v4_ctl_socket->sk->sk_prot->max_header); skb->dst = dst_clone(rxskb->dst); skb->h.raw = skb_push(skb, dccp_hdr_ack_len); dh = dccp_hdr(skb); memset(dh, 0, dccp_hdr_ack_len); /* Build DCCP header and checksum it. */ dh->dccph_type = DCCP_PKT_ACK; dh->dccph_sport = rxdh->dccph_dport; dh->dccph_dport = rxdh->dccph_sport; dh->dccph_doff = dccp_hdr_ack_len / 4; dh->dccph_x = 1; dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq); dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), DCCP_SKB_CB(rxskb)->dccpd_seq); bh_lock_sock(dccp_v4_ctl_socket->sk); err = ip_build_and_send_pkt(skb, dccp_v4_ctl_socket->sk, rxskb->nh.iph->daddr, rxskb->nh.iph->saddr, NULL); bh_unlock_sock(dccp_v4_ctl_socket->sk); if (err == NET_XMIT_CN || err == 0) { DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS); DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS); } }
static void dccp_v4_ctl_send_reset(const struct sock *sk, struct sk_buff *rxskb) { int err; const struct iphdr *rxiph; struct sk_buff *skb; struct dst_entry *dst; struct net *net = dev_net(skb_dst(rxskb)->dev); struct sock *ctl_sk = net->dccp.v4_ctl_sk; /* Never send a reset in response to a reset. */ if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET) return; if (skb_rtable(rxskb)->rt_type != RTN_LOCAL) return; dst = dccp_v4_route_skb(net, ctl_sk, rxskb); if (dst == NULL) return; skb = dccp_ctl_make_reset(ctl_sk, rxskb); if (skb == NULL) goto out; rxiph = ip_hdr(rxskb); dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr, rxiph->daddr); skb_dst_set(skb, dst_clone(dst)); local_bh_disable(); bh_lock_sock(ctl_sk); err = ip_build_and_send_pkt(skb, ctl_sk, rxiph->daddr, rxiph->saddr, NULL); bh_unlock_sock(ctl_sk); if (net_xmit_eval(err) == 0) { __DCCP_INC_STATS(DCCP_MIB_OUTSEGS); __DCCP_INC_STATS(DCCP_MIB_OUTRSTS); } local_bh_enable(); out: dst_release(dst); }