u8 ws; /* window scale, 0 to disable */
u8 num_sack_blocks; /* number of SACK blocks to include */
u8 hash_size; /* bytes in hash_location */
+ u8 bpf_opt_len; /* length of BPF hdr option */
__u8 *hash_location; /* temporary pointer, overloaded */
__u32 tsval, tsecr; /* need to include OPTION_TS */
struct tcp_fastopen_cookie *fastopen_cookie; /* Fast open cookie */
#endif
}
+#ifdef CONFIG_CGROUP_BPF
+/* req, syn_skb and synack_type are used when writing synack */
+static void bpf_skops_hdr_opt_len(struct sock *sk, struct sk_buff *skb,
+ struct request_sock *req,
+ struct sk_buff *syn_skb,
+ enum tcp_synack_type synack_type,
+ struct tcp_out_options *opts,
+ unsigned int *remaining)
+{
+ if (likely(!BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk),
+ BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG)) ||
+ !*remaining)
+ return;
+
+ /* The bpf running context preparation and the actual bpf prog
+ * calling will be implemented in a later PATCH together with
+ * other bpf pieces.
+ */
+}
+
+static void bpf_skops_write_hdr_opt(struct sock *sk, struct sk_buff *skb,
+ struct request_sock *req,
+ struct sk_buff *syn_skb,
+ enum tcp_synack_type synack_type,
+ struct tcp_out_options *opts)
+{
+ if (likely(!opts->bpf_opt_len))
+ return;
+
+ /* The bpf running context preparation and the actual bpf prog
+ * calling will be implemented in a later PATCH together with
+ * other bpf pieces.
+ */
+}
+#else
+static void bpf_skops_hdr_opt_len(struct sock *sk, struct sk_buff *skb,
+ struct request_sock *req,
+ struct sk_buff *syn_skb,
+ enum tcp_synack_type synack_type,
+ struct tcp_out_options *opts,
+ unsigned int *remaining)
+{
+}
+
+static void bpf_skops_write_hdr_opt(struct sock *sk, struct sk_buff *skb,
+ struct request_sock *req,
+ struct sk_buff *syn_skb,
+ enum tcp_synack_type synack_type,
+ struct tcp_out_options *opts)
+{
+}
+#endif
+
/* Write previously computed TCP options to the packet.
*
* Beware: Something in the Internet is very sensitive to the ordering of
}
}
+ bpf_skops_hdr_opt_len(sk, skb, NULL, NULL, 0, opts, &remaining);
+
return MAX_TCP_OPTION_SPACE - remaining;
}
struct tcp_out_options *opts,
const struct tcp_md5sig_key *md5,
struct tcp_fastopen_cookie *foc,
- enum tcp_synack_type synack_type)
+ enum tcp_synack_type synack_type,
+ struct sk_buff *syn_skb)
{
struct inet_request_sock *ireq = inet_rsk(req);
unsigned int remaining = MAX_TCP_OPTION_SPACE;
smc_set_option_cond(tcp_sk(sk), ireq, opts, &remaining);
+ bpf_skops_hdr_opt_len((struct sock *)sk, skb, req, syn_skb,
+ synack_type, opts, &remaining);
+
return MAX_TCP_OPTION_SPACE - remaining;
}
opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
}
+ if (unlikely(BPF_SOCK_OPS_TEST_FLAG(tp,
+ BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG))) {
+ unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
+
+ bpf_skops_hdr_opt_len(sk, skb, NULL, NULL, 0, opts, &remaining);
+
+ size = MAX_TCP_OPTION_SPACE - remaining;
+ }
+
return size;
}
}
#endif
+ /* BPF prog is the last one writing header option */
+ bpf_skops_write_hdr_opt(sk, skb, NULL, NULL, 0, &opts);
+
INDIRECT_CALL_INET(icsk->icsk_af_ops->send_check,
tcp_v6_send_check, tcp_v4_send_check,
sk, skb);
}
/**
- * tcp_make_synack - Prepare a SYN-ACK.
- * sk: listener socket
- * dst: dst entry attached to the SYNACK
- * req: request_sock pointer
- * foc: cookie for tcp fast open
- * synack_type: Type of synback to prepare
- *
- * Allocate one skb and build a SYNACK packet.
- * @dst is consumed : Caller should not use it again.
+ * tcp_make_synack - Allocate one skb and build a SYNACK packet.
+ * @sk: listener socket
+ * @dst: dst entry attached to the SYNACK. It is consumed and caller
+ * should not use it again.
+ * @req: request_sock pointer
+ * @foc: cookie for tcp fast open
+ * @synack_type: Type of synack to prepare
+ * @syn_skb: SYN packet just received. It could be NULL for rtx case.
*/
struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
struct request_sock *req,
struct tcp_fastopen_cookie *foc,
- enum tcp_synack_type synack_type)
+ enum tcp_synack_type synack_type,
+ struct sk_buff *syn_skb)
{
struct inet_request_sock *ireq = inet_rsk(req);
const struct tcp_sock *tp = tcp_sk(sk);
md5 = tcp_rsk(req)->af_specific->req_md5_lookup(sk, req_to_sk(req));
#endif
skb_set_hash(skb, tcp_rsk(req)->txhash, PKT_HASH_TYPE_L4);
+ /* bpf program will be interested in the tcp_flags */
+ TCP_SKB_CB(skb)->tcp_flags = TCPHDR_SYN | TCPHDR_ACK;
tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts, md5,
- foc, synack_type) + sizeof(*th);
+ foc, synack_type,
+ syn_skb) + sizeof(*th);
skb_push(skb, tcp_header_size);
skb_reset_transport_header(skb);
rcu_read_unlock();
#endif
+ bpf_skops_write_hdr_opt((struct sock *)sk, skb, req, syn_skb,
+ synack_type, &opts);
+
skb->skb_mstamp_ns = now;
tcp_add_tx_delay(skb, tp);
int res;
tcp_rsk(req)->txhash = net_tx_rndhash();
- res = af_ops->send_synack(sk, NULL, &fl, req, NULL, TCP_SYNACK_NORMAL);
+ res = af_ops->send_synack(sk, NULL, &fl, req, NULL, TCP_SYNACK_NORMAL,
+ NULL);
if (!res) {
__TCP_INC_STATS(sock_net(sk), TCP_MIB_RETRANSSEGS);
__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSYNRETRANS);