[PATCH bpf-next 4/8] bpf: add icsk_retransmits to bpf_tcp_sock

[Stanislav Fomichev]

Add some inet_connection_sock fields to bpf_tcp_sock that might be useful
for debugging congestion control issues.

Cc: Eric Dumazet <eduma...@google.com>
Cc: Priyaranjan Jha <priyar...@google.com>
Cc: Yuchung Cheng <ych...@google.com>
Cc: Soheil Hassas Yeganeh <soh...@google.com>
Signed-off-by: Stanislav Fomichev <s...@google.com>
---
 include/uapi/linux/bpf.h |  1 +
 net/core/filter.c        | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index bfb0b1a76684..ead27aebf491 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3078,6 +3078,7 @@ struct bpf_tcp_sock {
                                 */
        __u32 delivered;        /* Total data packets delivered incl. rexmits */
        __u32 delivered_ce;     /* Like the above but only ECE marked packets */
+       __u32 icsk_retransmits; /* Number of unrecovered [RTO] timeouts */
 };
 
 struct bpf_sock_tuple {
diff --git a/net/core/filter.c b/net/core/filter.c
index 3da4b6c38b46..089aaea0ccc6 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5544,7 +5544,8 @@ static const struct bpf_func_proto 
bpf_sock_addr_sk_lookup_udp_proto = {
 bool bpf_tcp_sock_is_valid_access(int off, int size, enum bpf_access_type type,
                                  struct bpf_insn_access_aux *info)
 {
-       if (off < 0 || off >= offsetofend(struct bpf_tcp_sock, delivered_ce))
+       if (off < 0 || off >= offsetofend(struct bpf_tcp_sock,
+                                         icsk_retransmits))
                return false;
 
        if (off % size != 0)
@@ -5575,6 +5576,20 @@ u32 bpf_tcp_sock_convert_ctx_access(enum bpf_access_type 
type,
                                      offsetof(struct tcp_sock, FIELD)); \
        } while (0)
 
+#define BPF_INET_SOCK_GET_COMMON(FIELD)                                        
\
+       do {                                                            \
+               BUILD_BUG_ON(FIELD_SIZEOF(struct inet_connection_sock,  \
+                                         FIELD) >                      \
+                            FIELD_SIZEOF(struct bpf_tcp_sock, FIELD)); \
+               *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(                 \
+                                       struct inet_connection_sock,    \
+                                       FIELD),                         \
+                                     si->dst_reg, si->src_reg,         \
+                                     offsetof(                         \
+                                       struct inet_connection_sock,    \
+                                       FIELD));                        \
+       } while (0)
+
        if (insn > insn_buf)
                return insn - insn_buf;
 
@@ -5661,6 +5676,9 @@ u32 bpf_tcp_sock_convert_ctx_access(enum bpf_access_type 
type,
        case offsetof(struct bpf_tcp_sock, delivered_ce):
                BPF_TCP_SOCK_GET_COMMON(delivered_ce);
                break;
+       case offsetof(struct bpf_tcp_sock, icsk_retransmits):
+               BPF_INET_SOCK_GET_COMMON(icsk_retransmits);
+               break;
        }
 
        return insn - insn_buf;
-- 
2.22.0.410.gd8fdbe21b5-goog