diff options
Diffstat (limited to 'src/pkg/net/dnsclient.go')
| -rw-r--r-- | src/pkg/net/dnsclient.go | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/src/pkg/net/dnsclient.go b/src/pkg/net/dnsclient.go index 280b19453..93c04f6b5 100644 --- a/src/pkg/net/dnsclient.go +++ b/src/pkg/net/dnsclient.go @@ -9,6 +9,7 @@ import ( "fmt" "os" "rand" + "sort" ) // DNSError represents a DNS lookup error. @@ -182,9 +183,9 @@ func (s byPriorityWeight) Less(i, j int) bool { (s[i].Priority == s[j].Priority && s[i].Weight < s[j].Weight) } -// shuffleSRVByWeight shuffles SRV records by weight using the algorithm +// shuffleByWeight shuffles SRV records by weight using the algorithm // described in RFC 2782. -func shuffleSRVByWeight(addrs []*SRV) { +func (addrs byPriorityWeight) shuffleByWeight() { sum := 0 for _, addr := range addrs { sum += int(addr.Weight) @@ -208,6 +209,19 @@ func shuffleSRVByWeight(addrs []*SRV) { } } +// sort reorders SRV records as specified in RFC 2782. +func (addrs byPriorityWeight) sort() { + sort.Sort(addrs) + i := 0 + for j := 1; j < len(addrs); j++ { + if addrs[i].Priority != addrs[j].Priority { + addrs[i:j].shuffleByWeight() + i = j + } + } + addrs[i:].shuffleByWeight() +} + // An MX represents a single DNS MX record. type MX struct { Host string @@ -222,3 +236,12 @@ func (s byPref) Len() int { return len(s) } func (s byPref) Less(i, j int) bool { return s[i].Pref < s[j].Pref } func (s byPref) Swap(i, j int) { s[i], s[j] = s[j], s[i] } + +// sort reorders MX records as specified in RFC 5321. +func (s byPref) sort() { + for i := range s { + j := rand.Intn(i + 1) + s[i], s[j] = s[j], s[i] + } + sort.Sort(s) +} |