tcp: prepare CC get_info() access from getsockopt()

We would like that optional info provided by Congestion Control
modules using netlink can also be read using getsockopt()

This patch changes get_info() to put this information in a buffer,
instead of skb, like tcp_get_info(), so that following patch
can reuse this common infrastructure.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/tcp.h b/include/net/tcp.h
index dd7b4ea..6d204f3 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -804,6 +804,8 @@ enum tcp_ca_ack_event_flags {
 /* Requires ECN/ECT set on all packets */
 #define TCP_CONG_NEEDS_ECN     0x2
 
+union tcp_cc_info;
+
 struct tcp_congestion_ops {
        struct list_head        list;
        u32 key;
@@ -829,7 +831,8 @@ struct tcp_congestion_ops {
        /* hook for packet ack accounting (optional) */
        void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
        /* get info for inet_diag (optional) */
-       int (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
+       size_t (*get_info)(struct sock *sk, u32 ext, int *attr,
+                          union tcp_cc_info *info);
 
        char            name[TCP_CA_NAME_MAX];
        struct module   *owner;

diff --git a/include/uapi/linux/inet_diag.h b/include/uapi/linux/inet_diag.h
index d65c0a0..c7093c7 100644 (file)
--- a/include/uapi/linux/inet_diag.h
+++ b/include/uapi/linux/inet_diag.h
@@ -143,4 +143,8 @@ struct tcp_dctcp_info {
        __u32   dctcp_ab_tot;
 };
 
+union tcp_cc_info {
+       struct tcpvegas_info    vegas;
+       struct tcp_dctcp_info   dctcp;
+};
 #endif /* _UAPI_INET_DIAG_H_ */

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index bb77ebd..4d32262 100644 (file)
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -224,14 +224,16 @@ int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk,
        handler->idiag_get_info(sk, r, info);
 
        if (sk->sk_state < TCP_TIME_WAIT) {
-               int err = 0;
+               union tcp_cc_info info;
+               size_t sz = 0;
+               int attr;
 
                rcu_read_lock();
                ca_ops = READ_ONCE(icsk->icsk_ca_ops);
                if (ca_ops && ca_ops->get_info)
-                       err = ca_ops->get_info(sk, ext, skb);
+                       sz = ca_ops->get_info(sk, ext, &attr, &info);
                rcu_read_unlock();
-               if (err < 0)
+               if (sz && nla_put(skb, attr, sz, &info) < 0)
                        goto errout;
        }
 

diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c
index 4376016..4c41c12 100644 (file)
--- a/net/ipv4/tcp_dctcp.c
+++ b/net/ipv4/tcp_dctcp.c
@@ -277,7 +277,8 @@ static void dctcp_cwnd_event(struct sock *sk, enum tcp_ca_event ev)
        }
 }
 
-static int dctcp_get_info(struct sock *sk, u32 ext, struct sk_buff *skb)
+static size_t dctcp_get_info(struct sock *sk, u32 ext, int *attr,
+                            union tcp_cc_info *info)
 {
        const struct dctcp *ca = inet_csk_ca(sk);
 
@@ -286,18 +287,17 @@ static int dctcp_get_info(struct sock *sk, u32 ext, struct sk_buff *skb)
         */
        if (ext & (1 << (INET_DIAG_DCTCPINFO - 1)) ||
            ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
-               struct tcp_dctcp_info info;
-
-               memset(&info, 0, sizeof(info));
+               memset(info, 0, sizeof(struct tcp_dctcp_info));
                if (inet_csk(sk)->icsk_ca_ops != &dctcp_reno) {
-                       info.dctcp_enabled = 1;
-                       info.dctcp_ce_state = (u16) ca->ce_state;
-                       info.dctcp_alpha = ca->dctcp_alpha;
-                       info.dctcp_ab_ecn = ca->acked_bytes_ecn;
-                       info.dctcp_ab_tot = ca->acked_bytes_total;
+                       info->dctcp.dctcp_enabled = 1;
+                       info->dctcp.dctcp_ce_state = (u16) ca->ce_state;
+                       info->dctcp.dctcp_alpha = ca->dctcp_alpha;
+                       info->dctcp.dctcp_ab_ecn = ca->acked_bytes_ecn;
+                       info->dctcp.dctcp_ab_tot = ca->acked_bytes_total;
                }
 
-               return nla_put(skb, INET_DIAG_DCTCPINFO, sizeof(info), &info);
+               *attr = INET_DIAG_DCTCPINFO;
+               return sizeof(*info);
        }
        return 0;
 }

diff --git a/net/ipv4/tcp_illinois.c b/net/ipv4/tcp_illinois.c
index 67476f0..f71002e 100644 (file)
--- a/net/ipv4/tcp_illinois.c
+++ b/net/ipv4/tcp_illinois.c
@@ -300,24 +300,25 @@ static u32 tcp_illinois_ssthresh(struct sock *sk)
 }
 
 /* Extract info for Tcp socket info provided via netlink. */
-static int tcp_illinois_info(struct sock *sk, u32 ext, struct sk_buff *skb)
+static size_t tcp_illinois_info(struct sock *sk, u32 ext, int *attr,
+                               union tcp_cc_info *info)
 {
        const struct illinois *ca = inet_csk_ca(sk);
 
        if (ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
-               struct tcpvegas_info info = {
-                       .tcpv_enabled = 1,
-                       .tcpv_rttcnt = ca->cnt_rtt,
-                       .tcpv_minrtt = ca->base_rtt,
-               };
+               info->vegas.tcpv_enabled = 1;
+               info->vegas.tcpv_rttcnt = ca->cnt_rtt;
+               info->vegas.tcpv_minrtt = ca->base_rtt;
+               info->vegas.tcpv_rtt = 0;
 
-               if (info.tcpv_rttcnt > 0) {
+               if (info->vegas.tcpv_rttcnt > 0) {
                        u64 t = ca->sum_rtt;
 
-                       do_div(t, info.tcpv_rttcnt);
-                       info.tcpv_rtt = t;
+                       do_div(t, info->vegas.tcpv_rttcnt);
+                       info->vegas.tcpv_rtt = t;
                }
-               return nla_put(skb, INET_DIAG_VEGASINFO, sizeof(info), &info);
+               *attr = INET_DIAG_VEGASINFO;
+               return sizeof(struct tcpvegas_info);
        }
        return 0;
 }

diff --git a/net/ipv4/tcp_vegas.c b/net/ipv4/tcp_vegas.c
index c71a1b8..a6cea1d 100644 (file)
--- a/net/ipv4/tcp_vegas.c
+++ b/net/ipv4/tcp_vegas.c
@@ -286,18 +286,19 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked)
 }
 
 /* Extract info for Tcp socket info provided via netlink. */
-int tcp_vegas_get_info(struct sock *sk, u32 ext, struct sk_buff *skb)
+size_t tcp_vegas_get_info(struct sock *sk, u32 ext, int *attr,
+                         union tcp_cc_info *info)
 {
        const struct vegas *ca = inet_csk_ca(sk);
+
        if (ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
-               struct tcpvegas_info info = {
-                       .tcpv_enabled = ca->doing_vegas_now,
-                       .tcpv_rttcnt = ca->cntRTT,
-                       .tcpv_rtt = ca->baseRTT,
-                       .tcpv_minrtt = ca->minRTT,
-               };
-
-               return nla_put(skb, INET_DIAG_VEGASINFO, sizeof(info), &info);
+               info->vegas.tcpv_enabled = ca->doing_vegas_now,
+               info->vegas.tcpv_rttcnt = ca->cntRTT,
+               info->vegas.tcpv_rtt = ca->baseRTT,
+               info->vegas.tcpv_minrtt = ca->minRTT,
+
+               *attr = INET_DIAG_VEGASINFO;
+               return sizeof(struct tcpvegas_info);
        }
        return 0;
 }

diff --git a/net/ipv4/tcp_vegas.h b/net/ipv4/tcp_vegas.h
index e8a6b33..ef9da53 100644 (file)
--- a/net/ipv4/tcp_vegas.h
+++ b/net/ipv4/tcp_vegas.h
@@ -19,6 +19,7 @@ void tcp_vegas_init(struct sock *sk);
 void tcp_vegas_state(struct sock *sk, u8 ca_state);
 void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, s32 rtt_us);
 void tcp_vegas_cwnd_event(struct sock *sk, enum tcp_ca_event event);
-int tcp_vegas_get_info(struct sock *sk, u32 ext, struct sk_buff *skb);
+size_t tcp_vegas_get_info(struct sock *sk, u32 ext, int *attr,
+                         union tcp_cc_info *info);
 
 #endif /* __TCP_VEGAS_H */