add comments and resolve nits

Author: sukunrt

Diff for: p2p/protocol/autonatv2/autonat.go

@@ -142,11 +142,11 @@ func (an *AutoNAT) CheckReachability(ctx context.Context, highPriorityAddrs []ma
 func (an *AutoNAT) validPeer() peer.ID {
 	peers := an.host.Peerstore().Peers()
 	idx := 0
-	for _, p := range an.host.Peerstore().Peers() {
-		if proto, err := an.host.Peerstore().SupportsProtocols(p, DialProtocol); len(proto) == 0 || err != nil {
+	for i := 0; i < len(peers); i++ {
+		if proto, err := an.host.Peerstore().SupportsProtocols(peers[i], DialProtocol); len(proto) == 0 || err != nil {
 			continue
 		}
-		peers[idx] = p
+		peers[idx] = peers[i]
 		idx++
 	}
 	if idx == 0 {

Diff for: p2p/protocol/autonatv2/client.go

@@ -18,18 +18,24 @@ import (
 
 //go:generate protoc --go_out=. --go_opt=Mpbv2/autonat.proto=./pbv2 pbv2/autonat.proto
 
+// Client implements the client for making dial requests for AutoNAT v2. It verifies successful
+// dials and provides an option to send data for amplification attack prevention.
 type Client struct {
 	host       host.Host
 	dialCharge []byte
 
-	mu            sync.Mutex
+	mu sync.Mutex
+	// attemptQueues maps nonce to the channel for providing the local multiaddr of the connection
+	// the nonce was received on
 	attemptQueues map[uint64]chan ma.Multiaddr
 }
 
 func NewClient(h host.Host) *Client {
 	return &Client{host: h, dialCharge: make([]byte, 4096), attemptQueues: make(map[uint64]chan ma.Multiaddr)}
 }
 
+// CheckReachability verifies address reachability with a AutoNAT v2 server p. It'll provide data for amplification
+// attack prevention for high priority addresses and not for low priority addresses.
 func (ac *Client) CheckReachability(ctx context.Context, p peer.ID, highPriorityAddrs []ma.Multiaddr, lowPriorityAddrs []ma.Multiaddr) ([]Result, error) {
 	ctx, cancel := context.WithTimeout(ctx, streamTimeout)
 	defer cancel()

Diff for: p2p/protocol/autonatv2/server.go

@@ -18,7 +18,6 @@ import (
 	"golang.org/x/exp/rand"
 )
 
-
 type dataRequestPolicyFunc = func(s network.Stream, dialAddr ma.Multiaddr) bool
 
 const (
@@ -268,7 +267,7 @@ func (r *rateLimiter) Accept(p peer.ID) bool {
 func (r *rateLimiter) cleanup(p peer.ID, now time.Time) {
 	idx := len(r.reqs)
 	for i, t := range r.reqs {
-		if now.Sub(t).Minutes() <= 1 {
+		if now.Sub(t) < time.Minute {
 			idx = i
 			break
 		}
@@ -277,7 +276,7 @@ func (r *rateLimiter) cleanup(p peer.ID, now time.Time) {
 
 	idx = len(r.peerReqs[p])
 	for i, t := range r.peerReqs[p] {
-		if now.Sub(t).Minutes() <= 1 {
+		if now.Sub(t) < time.Minute {
 			idx = i
 			break
 		}