static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb) { const struct dccp_hdr *dh = dccp_hdr(skb); const struct iphdr *iph = ip_hdr(skb); struct sock *nsk; struct request_sock **prev; /* Find possible connection requests. */ struct request_sock *req = inet_csk_search_req(sk, &prev, dh->dccph_sport, iph->saddr, iph->daddr); if (req != NULL) return dccp_check_req(sk, skb, req, prev); nsk = inet_lookup_established(&dccp_hashinfo, iph->saddr, dh->dccph_sport, iph->daddr, dh->dccph_dport, inet_iif(skb)); if (nsk != NULL) { if (nsk->sk_state != DCCP_TIME_WAIT) { bh_lock_sock(nsk); return nsk; } inet_twsk_put(inet_twsk(nsk)); return NULL; } return sk; }
/* this is called when real data arrives */ static int dccp_v4_rcv(struct sk_buff *skb) { const struct dccp_hdr *dh; const struct iphdr *iph; struct sock *sk; int min_cov; /* Step 1: Check header basics */ if (dccp_invalid_packet(skb)) goto discard_it; iph = ip_hdr(skb); /* Step 1: If header checksum is incorrect, drop packet and return */ if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) { DCCP_WARN("dropped packet with invalid checksum\n"); goto discard_it; } dh = dccp_hdr(skb); DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh); DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type; dccp_pr_debug("%8.8s src=%pI4@%-5d dst=%pI4@%-5d seq=%llu", dccp_packet_name(dh->dccph_type), &iph->saddr, ntohs(dh->dccph_sport), &iph->daddr, ntohs(dh->dccph_dport), (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq); if (dccp_packet_without_ack(skb)) { DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ; dccp_pr_debug_cat("\n"); } else { DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long) DCCP_SKB_CB(skb)->dccpd_ack_seq); } lookup: sk = __inet_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh), dh->dccph_sport, dh->dccph_dport); if (!sk) { dccp_pr_debug("failed to look up flow ID in table and " "get corresponding socket\n"); goto no_dccp_socket; } /* * Step 2: * ... or S.state == TIMEWAIT, * Generate Reset(No Connection) unless P.type == Reset * Drop packet and return */ if (sk->sk_state == DCCP_TIME_WAIT) { dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n"); inet_twsk_put(inet_twsk(sk)); goto no_dccp_socket; } if (sk->sk_state == DCCP_NEW_SYN_RECV) { struct request_sock *req = inet_reqsk(sk); struct sock *nsk; sk = req->rsk_listener; if (unlikely(sk->sk_state != DCCP_LISTEN)) { inet_csk_reqsk_queue_drop_and_put(sk, req); goto lookup; } sock_hold(sk); nsk = dccp_check_req(sk, skb, req); if (!nsk) { reqsk_put(req); goto discard_and_relse; } if (nsk == sk) { reqsk_put(req); } else if (dccp_child_process(sk, nsk, skb)) { dccp_v4_ctl_send_reset(sk, skb); goto discard_and_relse; } else { sock_put(sk); return 0; } } /* * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage * o if MinCsCov = 0, only packets with CsCov = 0 are accepted * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov */ min_cov = dccp_sk(sk)->dccps_pcrlen; if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) { dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n", dh->dccph_cscov, min_cov); /* FIXME: "Such packets SHOULD be reported using Data Dropped * options (Section 11.7) with Drop Code 0, Protocol * Constraints." */ goto discard_and_relse; } if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) goto discard_and_relse; nf_reset(skb); return sk_receive_skb(sk, skb, 1); no_dccp_socket: if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) goto discard_it; /* * Step 2: * If no socket ... * Generate Reset(No Connection) unless P.type == Reset * Drop packet and return */ if (dh->dccph_type != DCCP_PKT_RESET) { DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; dccp_v4_ctl_send_reset(sk, skb); } discard_it: kfree_skb(skb); return 0; discard_and_relse: sock_put(sk); goto discard_it; }
static int dccp_v6_rcv(struct sk_buff *skb) { const struct dccp_hdr *dh; bool refcounted; struct sock *sk; int min_cov; /* Step 1: Check header basics */ if (dccp_invalid_packet(skb)) goto discard_it; /* Step 1: If header checksum is incorrect, drop packet and return. */ if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr)) { DCCP_WARN("dropped packet with invalid checksum\n"); goto discard_it; } dh = dccp_hdr(skb); DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh); DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type; if (dccp_packet_without_ack(skb)) DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ; else DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb); lookup: sk = __inet6_lookup_skb(&dccp_hashinfo, skb, __dccp_hdr_len(dh), dh->dccph_sport, dh->dccph_dport, inet6_iif(skb), &refcounted); if (!sk) { dccp_pr_debug("failed to look up flow ID in table and " "get corresponding socket\n"); goto no_dccp_socket; } /* * Step 2: * ... or S.state == TIMEWAIT, * Generate Reset(No Connection) unless P.type == Reset * Drop packet and return */ if (sk->sk_state == DCCP_TIME_WAIT) { dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n"); inet_twsk_put(inet_twsk(sk)); goto no_dccp_socket; } if (sk->sk_state == DCCP_NEW_SYN_RECV) { struct request_sock *req = inet_reqsk(sk); struct sock *nsk; sk = req->rsk_listener; if (unlikely(sk->sk_state != DCCP_LISTEN)) { inet_csk_reqsk_queue_drop_and_put(sk, req); goto lookup; } sock_hold(sk); refcounted = true; nsk = dccp_check_req(sk, skb, req); if (!nsk) { reqsk_put(req); goto discard_and_relse; } if (nsk == sk) { reqsk_put(req); } else if (dccp_child_process(sk, nsk, skb)) { dccp_v6_ctl_send_reset(sk, skb); goto discard_and_relse; } else { sock_put(sk); return 0; } } /* * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage * o if MinCsCov = 0, only packets with CsCov = 0 are accepted * o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov */ min_cov = dccp_sk(sk)->dccps_pcrlen; if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov)) { dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n", dh->dccph_cscov, min_cov); /* FIXME: send Data Dropped option (see also dccp_v4_rcv) */ goto discard_and_relse; } if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) goto discard_and_relse; return sk_receive_skb(sk, skb, 1) ? -1 : 0; no_dccp_socket: if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) goto discard_it; /* * Step 2: * If no socket ... * Generate Reset(No Connection) unless P.type == Reset * Drop packet and return */ if (dh->dccph_type != DCCP_PKT_RESET) { DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; dccp_v6_ctl_send_reset(sk, skb); } discard_it: kfree_skb(skb); return 0; discard_and_relse: if (refcounted) sock_put(sk); goto discard_it; }