net: tcp_probe: add IPv6 support

The tcp_probe currently only supports analysis of IPv4 connections.
Therefore, it would be nice to have IPv6 supported as well. Since we
have the recently added %pISpc specifier that is IPv4/IPv6 generic,
build related sockaddress structures from the flow information and
pass this to our format string. Tested with SSH and HTTP sessions
on IPv4 and IPv6.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 44 insertions, 10 deletions

diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c
index a2392f48ba35..301a3effe579 100644
--- a/net/ipv4/tcp_probe.c
+++ b/net/ipv4/tcp_probe.c
@@ -54,8 +54,11 @@ static const char procname[] = "tcpprobe";
 
 struct tcp_log {
         ktime_t tstamp;
-        __be32  saddr, daddr;
-        __be16  sport, dport;
+        union {
+                struct sockaddr         raw;
+                struct sockaddr_in      v4;
+                struct sockaddr_in6     v6;
+        }       src, dst;
         u16     length;
         u32     snd_nxt;
         u32     snd_una;
@@ -87,6 +90,30 @@ static inline int tcp_probe_avail(void)
         return bufsize - tcp_probe_used() - 1;
 }
 
+#define tcp_probe_copy_fl_to_si4(inet, si4, mem)                \
+        do {                                                    \
+                si4.sin_family = AF_INET;                       \
+                si4.sin_port = inet->inet_##mem##port;          \
+                si4.sin_addr.s_addr = inet->inet_##mem##addr;   \
+        } while (0)                                             \
+
+#if IS_ENABLED(CONFIG_IPV6)
+#define tcp_probe_copy_fl_to_si6(inet, si6, mem)                \
+        do {                                                    \
+                struct ipv6_pinfo *pi6 = inet->pinet6;          \
+                si6.sin6_family = AF_INET6;                     \
+                si6.sin6_port = inet->inet_##mem##port;         \
+                si6.sin6_addr = pi6->mem##addr;                 \
+                si6.sin6_flowinfo = 0; /* No need here. */      \
+                si6.sin6_scope_id = 0;  /* No need here. */     \
+        } while (0)
+#else
+#define tcp_probe_copy_fl_to_si6(fl, si6, mem)                  \
+        do {                                                    \
+                memset(&si6, 0, sizeof(si6));                   \
+        } while (0)
+#endif
+
 /*
  * Hook inserted to be called before each receive packet.
  * Note: arguments must match tcp_rcv_established()!
@@ -108,10 +135,19 @@ static int jtcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                         struct tcp_log *p = tcp_probe.log + tcp_probe.head;
 
                         p->tstamp = ktime_get();
-                        p->saddr = inet->inet_saddr;
-                        p->sport = inet->inet_sport;
-                        p->daddr = inet->inet_daddr;
-                        p->dport = inet->inet_dport;
+                        switch (sk->sk_family) {
+                        case AF_INET:
+                                tcp_probe_copy_fl_to_si4(inet, p->src.v4, s);
+                                tcp_probe_copy_fl_to_si4(inet, p->dst.v4, d);
+                                break;
+                        case AF_INET6:
+                                tcp_probe_copy_fl_to_si6(inet, p->src.v6, s);
+                                tcp_probe_copy_fl_to_si6(inet, p->dst.v6, d);
+                                break;
+                        default:
+                                BUG();
+                        }
+
                         p->length = skb->len;
                         p->snd_nxt = tp->snd_nxt;
                         p->snd_una = tp->snd_una;
@@ -159,12 +195,10 @@ static int tcpprobe_sprint(char *tbuf, int n)
                 = ktime_to_timespec(ktime_sub(p->tstamp, tcp_probe.start));
 
         return scnprintf(tbuf, n,
-                        "%lu.%09lu %pI4:%u %pI4:%u %d %#x %#x %u %u %u %u %u\n",
+                        "%lu.%09lu %pISpc %pISpc %d %#x %#x %u %u %u %u %u\n",
                         (unsigned long) tv.tv_sec,
                         (unsigned long) tv.tv_nsec,
-                        &p->saddr, ntohs(p->sport),
-                        &p->daddr, ntohs(p->dport),
-                        p->length, p->snd_nxt, p->snd_una,
+                        &p->src, &p->dst, p->length, p->snd_nxt, p->snd_una,
                         p->snd_cwnd, p->ssthresh, p->snd_wnd, p->srtt, p->rcv_wnd);
 }