tracing: document that peer addrs can be >68 chars

A v3 onion address with a `:` and a five digit port has a length of
68 chars. As noted in
bitcoin/bitcoin#25832 (comment)
peers e.g. added via hostname might have a longer CNode::m_addr_name.
These might be cut off in tracing tools.

Author: 0xB10C

doc/tracing.md

@@ -55,14 +55,17 @@ The currently available tracepoints are listed here.
 
 ### Context `net`
 
+[^address-length]: An Onion v3 address with a `:` and a five digit port has 68
+  chars. However, addresses of peers added with host names might be longer.
+
 #### Tracepoint `net:inbound_message`
 
 Is called when a message is received from a peer over the P2P network. Passes
 information about our peer, the connection and the message as arguments.
 
 Arguments passed:
 1. Peer ID as `int64`
-2. Peer Address and Port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (max. length 68 characters)
+2. Peer Address and Port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (normally up to 68 characters[^address-length])
 3. Connection Type (inbound, feeler, outbound-full-relay, ...) as `pointer to C-style String` (max. length 20 characters)
 4. Message Type (inv, ping, getdata, addrv2, ...) as `pointer to C-style String` (max. length 20 characters)
 5. Message Size in bytes as `uint64`
@@ -81,7 +84,7 @@ information about our peer, the connection and the message as arguments.
 
 Arguments passed:
 1. Peer ID as `int64`
-2. Peer Address and Port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (max. length 68 characters)
+2. Peer Address and Port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (normally up to 68 characters[^address-length])
 3. Connection Type (inbound, feeler, outbound-full-relay, ...) as `pointer to C-style String` (max. length 20 characters)
 4. Message Type (inv, ping, getdata, addrv2, ...) as `pointer to C-style String` (max. length 20 characters)
 5. Message Size in bytes as `uint64`
@@ -100,7 +103,7 @@ the peer and the number of inbound connections including the newly opened connec
 
 Arguments passed:
 1. Peer ID as `int64`
-2. Peer address and port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (max. length 68 characters)
+2. Peer address and port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (normally up to 68 characters[^address-length])
 3. Connection Type (inbound, feeler, outbound-full-relay, ...) as `pointer to C-style String` (max. length 20 characters)
 4. Network the peer connects from as `uint32` (1 = IPv4, 2 = IPv6, 3 = Onion, 4 = I2P, 5 = CJDNS). See `Network` enum in `netaddress.h`.
 5. Number of existing inbound connections as `uint64` including the newly opened inbound connection.
@@ -112,7 +115,7 @@ the peer and the number of outbound connections including the newly opened conne
 
 Arguments passed:
 1. Peer ID as `int64`
-2. Peer address and port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (max. length 68 characters)
+2. Peer address and port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (normally up to 68 characters[^address-length])
 3. Connection Type (inbound, feeler, outbound-full-relay, ...) as `pointer to C-style String` (max. length 20 characters)
 4. Network of the peer as `uint32` (1 = IPv4, 2 = IPv6, 3 = Onion, 4 = I2P, 5 = CJDNS). See `Network` enum in `netaddress.h`.
 5. Number of existing outbound connections as `uint64` including the newly opened outbound connection.
@@ -123,7 +126,7 @@ Is called when a inbound connection is evicted by us. Passes information about t
 
 Arguments passed:
 1. Peer ID as `int64`
-2. Peer address and port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (max. length 68 characters)
+2. Peer address and port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (normally up to 68 characters[^address-length])
 3. Connection Type (inbound, feeler, outbound-full-relay, ...) as `pointer to C-style String` (max. length 20 characters)
 4. Network the peer connects from as `uint32` (1 = IPv4, 2 = IPv6, 3 = Onion, 4 = I2P, 5 = CJDNS). See `Network` enum in `netaddress.h`.
 5. Connection established UNIX epoch timestamp in seconds as `uint64`.
@@ -144,7 +147,7 @@ and the time at connection establishment.
 
 Arguments passed:
 1. Peer ID as `int64`
-2. Peer address and port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (max. length 68 characters)
+2. Peer address and port (IPv4, IPv6, Tor v3, I2P, ...) as `pointer to C-style String` (normally up to 68 characters[^address-length])
 3. Connection Type (inbound, feeler, outbound-full-relay, ...) as `pointer to C-style String` (max. length 20 characters)
 4. Network the peer connects from as `uint32` (1 = IPv4, 2 = IPv6, 3 = Onion, 4 = I2P, 5 = CJDNS). See `Network` enum in `netaddress.h`.
 5. Connection established UNIX epoch timestamp in seconds as `uint64`.