Implement client timeouts for target.remote and target.smtp

Closes #239.

docs/man/maddy-targets.5.scd

@@ -128,6 +128,34 @@ per-source/per-destination are as observed when message exits the server.
 
 Choose the local IP to bind for outbound SMTP connections.
 
+*Syntax*: connect_timeout _duration_ ++
+*Default*: 5m
+
+Timeout for TCP connection establishment.
+
+RFC 5321 recommends 5 minutes for "initial greeting" that includes TCP
+handshake. maddy uses two separate timers - one for "dialing" (DNS A/AAAA
+lookup + TCP handshake) and another for "initial greeting". This directive
+configures the former. The latter is not configurable and is hardcoded to be
+5 minutes.
+
+*Syntax*: command_timeout _duration_ ++
+*Default*: 5m
+
+Timeout for any SMTP command (EHLO, MAIL, RCPT, DATA, etc).
+
+If STARTTLS is used this timeout also applies to TLS handshake.
+
+RFC 5321 recommends 5 minutes for MAIL/RCPT and 3 minutes for
+DATA.
+
+*Syntax*: submission_timeout _duration_ ++
+*Default*: 12m
+
+Time to wait after the entire message is sent (after "final dot").
+
+RFC 5321 recommends 10 minutes.
+
 *Syntax*: debug _boolean_ ++
 *Default*: global directive value
 
@@ -333,6 +361,9 @@ target.smtp {
     require_yes no
     auth off
     targets tcp://127.0.0.1:2525
+    connect_timeout 5m
+    command_timeout 5m
+    submission_timeout 12m
 }
 ```
 
@@ -405,6 +436,21 @@ TLS).
 Multiple addresses can be specified, they will be tried in order until connection to
 one succeeds (including TLS handshake if TLS is required).
 
+*Syntax*: connect_timeout _duration_ ++
+*Default*: 5m
+
+Same as for target.remote.
+
+*Syntax*: command_timeout _duration_ ++
+*Default*: 5m
+
+Same as for target.remote.
+
+*Syntax*: submission_timeout _duration_ ++
+*Default*: 12m
+
+Same as for target.remote.
+
 # LMTP transparent forwarding module (target.lmtp)
 
 The 'target.lmtp' module is similar to 'target.smtp' and supports all

go.mod

@@ -18,7 +18,7 @@ require (
 	github.com/emersion/go-milter v0.2.0
 	github.com/emersion/go-msgauth v0.5.0
 	github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21
-	github.com/emersion/go-smtp v0.13.1-0.20200724113925-09421d11e5b0
+	github.com/emersion/go-smtp v0.15.1-0.20210705155248-26eb4814e227
 	github.com/foxcpp/go-dovecot-sasl v0.0.0-20200522223722-c4699d7a24bf
 	github.com/foxcpp/go-imap-i18nlevel v0.0.0-20200208001533-d6ec88553005
 	github.com/foxcpp/go-imap-namespace v0.0.0-20200722130255-93092adf35f1

go.sum

@@ -41,7 +41,6 @@ github.com/codahale/hdrhistogram v0.0.0-20161010025455-3a0bb77429bd/go.mod h1:sE
 github.com/coreos/go-semver v0.2.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3EedlOD2RNk=
 github.com/coreos/go-systemd v0.0.0-20180511133405-39ca1b05acc7/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/pkg v0.0.0-20160727233714-3ac0863d7acf/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
-github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d h1:U+s90UTSYgptZMwQh2aRr3LuazLJIa+Pg3Kc1ylSYVY=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/cpuguy83/go-md2man/v2 v2.0.0 h1:EoUDS0afbrsXAZ9YQ9jdu/mZ2sXgT1/2yyNng4PGlyM=
 github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
@@ -57,9 +56,7 @@ github.com/eapache/queue v1.1.0/go.mod h1:6eCeP0CKFpHLu8blIFXhExK/dRa7WDZfr6jVFP
 github.com/edsrzf/mmap-go v1.0.0/go.mod h1:YO35OhQPt3KJa3ryjFM5Bs14WD66h8eGKpfaBNrHW5M=
 github.com/emersion/go-imap v1.0.0-beta.4.0.20190504114255-4d5af3d05147/go.mod h1:mOPegfAgLVXbhRm1bh2JTX08z2Y3HYmKYpbrKDeAzsQ=
 github.com/emersion/go-imap v1.0.0/go.mod h1:MEiDDwwQFcZ+L45Pa68jNGv0qU9kbW+SJzwDpvSfX1s=
-github.com/emersion/go-imap v1.0.3 h1:5eEee8/DTSIPfliiWqwfvjPGkU8bBtvOy/Wx+eeXzO4=
 github.com/emersion/go-imap v1.0.3/go.mod h1:yKASt+C3ZiDAiCSssxg9caIckWF/JG7ZQTO7GAmvicU=
-github.com/emersion/go-imap v1.0.4 h1:uiCAIHM6Z5Jwkma1zdNDWWXxSCqb+/xHBkHflD7XBro=
 github.com/emersion/go-imap v1.0.4/go.mod h1:yKASt+C3ZiDAiCSssxg9caIckWF/JG7ZQTO7GAmvicU=
 github.com/emersion/go-imap v1.0.6-0.20200708083111-011063d6c9df h1:Vlwnsd5P5s+ek+wzEXbZ/g9tUBndVQAb3E1/+/ya3UQ=
 github.com/emersion/go-imap v1.0.6-0.20200708083111-011063d6c9df/go.mod h1:yKASt+C3ZiDAiCSssxg9caIckWF/JG7ZQTO7GAmvicU=
@@ -69,26 +66,20 @@ github.com/emersion/go-imap-compress v0.0.0-20170105185004-f036eda44681 h1:xihom
 github.com/emersion/go-imap-compress v0.0.0-20170105185004-f036eda44681/go.mod h1:2Ro1PbmiqYiRe5Ct2sGR5hHaKSVHeRpVZwXx8vyYt98=
 github.com/emersion/go-imap-idle v0.0.0-20200601154248-f05f54664cc4 h1:/JIALzmCduf5o8TWJSiOBzTb9+R0SChwElUrJLlp2po=
 github.com/emersion/go-imap-idle v0.0.0-20200601154248-f05f54664cc4/go.mod h1:o14zPKCmEH5WC1vU5SdPoZGgNvQx7zzKSnxPQlobo78=
-github.com/emersion/go-imap-move v0.0.0-20180601155324-5eb20cb834bf h1:TmRfuPmhrwAhWKu2XaBaY9N+anRRDBO+E8VRVO9g3fY=
 github.com/emersion/go-imap-move v0.0.0-20180601155324-5eb20cb834bf/go.mod h1:QuMaZcKFDVI0yCrnAbPLfbwllz1wtOrZH8/vZ5yzp4w=
 github.com/emersion/go-imap-move v0.0.0-20190710073258-6e5a51a5b342 h1:5p1t3e1PomYgLWwEwhwEU5kVBwcyAcVrOpexv8AeZx0=
 github.com/emersion/go-imap-move v0.0.0-20190710073258-6e5a51a5b342/go.mod h1:QuMaZcKFDVI0yCrnAbPLfbwllz1wtOrZH8/vZ5yzp4w=
 github.com/emersion/go-imap-sortthread v1.1.1-0.20200727121200-18e5fb409fed h1:O1GZQnAy76K/DHEp2+S8ZI5hRmkTVNkCLc4Xb0c/RL8=
 github.com/emersion/go-imap-sortthread v1.1.1-0.20200727121200-18e5fb409fed/go.mod h1:opHOzblOHZKQM1JEy+GPk1217giNLa7kleyWTN06qnc=
-github.com/emersion/go-imap-specialuse v0.0.0-20161227184202-ba031ced6a62 h1:4ZAfwfc8aDlj26kkEap1UDSwwDnJp9Ie8Uj1MSXAkPk=
 github.com/emersion/go-imap-specialuse v0.0.0-20161227184202-ba031ced6a62/go.mod h1:/nybxhI8kXom8Tw6BrHMl42usALvka6meORflnnYwe4=
 github.com/emersion/go-imap-specialuse v0.0.0-20200722111535-598ff00e4075 h1:z8TiDE4yqtzNeA1yb6ZRcktd+BHlXQbKGugvmDuc488=
 github.com/emersion/go-imap-specialuse v0.0.0-20200722111535-598ff00e4075/go.mod h1:/nybxhI8kXom8Tw6BrHMl42usALvka6meORflnnYwe4=
 github.com/emersion/go-imap-unselect v0.0.0-20171113212723-b985794e5f26 h1:FiSb8+XBQQSkcX3ubr+1tAtlRJBYaFmRZqOAweZ9Wy8=
 github.com/emersion/go-imap-unselect v0.0.0-20171113212723-b985794e5f26/go.mod h1:+gnnZx3Mg3MnCzZrv0eZdp5puxXQUgGT/6N6L7ShKfM=
-github.com/emersion/go-message v0.9.1 h1:s6HoJ6t+1wHWEs0G/QVR1r5bb6nvx2/b6DuQfknit14=
 github.com/emersion/go-message v0.9.1/go.mod h1:m3cK90skCWxm5sIMs1sXxly4Tn9Plvcf6eayHZJ1NzM=
-github.com/emersion/go-message v0.10.3 h1:4pajGb3Rq+gHLfRcWysgcwtGRNgLpB8LC6X/vRZ89d0=
 github.com/emersion/go-message v0.10.3/go.mod h1:3h+HsGTCFHmk4ngJ2IV/YPhdlaOcR6hcgqM3yca9v7c=
 github.com/emersion/go-message v0.10.4-0.20190609165112-592ace5bc1ca/go.mod h1:3h+HsGTCFHmk4ngJ2IV/YPhdlaOcR6hcgqM3yca9v7c=
-github.com/emersion/go-message v0.11.1 h1:0C/S4JIXDTSfXB1vpqdimAYyK4+79fgEAMQ0dSL+Kac=
 github.com/emersion/go-message v0.11.1/go.mod h1:C4jnca5HOTo4bGN9YdqNQM9sITuT3Y0K6bSUw9RklvY=
-github.com/emersion/go-message v0.11.2 h1:oxO9SQ+3wgBAQRdk07eqfkCJ26Tl8ZHF7CcpGVoE00o=
 github.com/emersion/go-message v0.11.2/go.mod h1:C4jnca5HOTo4bGN9YdqNQM9sITuT3Y0K6bSUw9RklvY=
 github.com/emersion/go-message v0.12.0 h1:mZnv35eZ6lB6EftTQBgYXspOH0FQdhpFhSUhA9i6/Zg=
 github.com/emersion/go-message v0.12.0/go.mod h1:C4jnca5HOTo4bGN9YdqNQM9sITuT3Y0K6bSUw9RklvY=
@@ -97,16 +88,16 @@ github.com/emersion/go-milter v0.2.0 h1:TaKXziGFoIZmYz0iWb80GxXBFQsUjrQdk9skw4+D
 github.com/emersion/go-milter v0.2.0/go.mod h1:ablHK0pbLB83kMFBznp/Rj8aV+Kc3jw8cxzzmCNLIOY=
 github.com/emersion/go-msgauth v0.5.0 h1:sYB3vvl+Lrs5zhKXhbp10ChQHxCdK13KLh7fjLNE/SE=
 github.com/emersion/go-msgauth v0.5.0/go.mod h1:7r9HUSXL1dq+KK7Xqg0JlyBxNFGf5+JouRvSz4wBZCQ=
-github.com/emersion/go-sasl v0.0.0-20161116183048-7e096a0a6197 h1:rDJPbyliyym8ZL/Wt71kdolp6yaD4fLIQz638E6JEt0=
 github.com/emersion/go-sasl v0.0.0-20161116183048-7e096a0a6197/go.mod h1:G/dpzLu16WtQpBfQ/z3LYiYJn3ZhKSGWn83fyoyQe/k=
 github.com/emersion/go-sasl v0.0.0-20190520160400-47d427600317/go.mod h1:G/dpzLu16WtQpBfQ/z3LYiYJn3ZhKSGWn83fyoyQe/k=
 github.com/emersion/go-sasl v0.0.0-20190817083125-240c8404624e/go.mod h1:G/dpzLu16WtQpBfQ/z3LYiYJn3ZhKSGWn83fyoyQe/k=
-github.com/emersion/go-sasl v0.0.0-20191210011802-430746ea8b9b h1:uhWtEWBHgop1rqEk2klKaxPAkVDCXexai6hSuRQ7Nvs=
 github.com/emersion/go-sasl v0.0.0-20191210011802-430746ea8b9b/go.mod h1:G/dpzLu16WtQpBfQ/z3LYiYJn3ZhKSGWn83fyoyQe/k=
 github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21 h1:OJyUGMJTzHTd1XQp98QTaHernxMYzRaOasRir9hUlFQ=
 github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21/go.mod h1:iL2twTeMvZnrg54ZoPDNfJaJaqy0xIQFuBdrLsmspwQ=
 github.com/emersion/go-smtp v0.13.1-0.20200724113925-09421d11e5b0 h1:110GWeGuYRg82JJxTAucVmonobbR79ubOWFvDAE5rQM=
 github.com/emersion/go-smtp v0.13.1-0.20200724113925-09421d11e5b0/go.mod h1:qm27SGYgoIPRot6ubfQ/GpiPy/g3PaZAVRxiO/sDUgQ=
+github.com/emersion/go-smtp v0.15.1-0.20210705155248-26eb4814e227 h1:LsNh1Xid8MkhJc0OiAbacbIUreFLdJHtERozP3/use0=
+github.com/emersion/go-smtp v0.15.1-0.20210705155248-26eb4814e227/go.mod h1:qm27SGYgoIPRot6ubfQ/GpiPy/g3PaZAVRxiO/sDUgQ=
 github.com/emersion/go-textwrapper v0.0.0-20160606182133-d0e65e56babe h1:40SWqY0zE3qCi6ZrtTf5OUdNm5lDnGnjRSq9GgmeTrg=
 github.com/emersion/go-textwrapper v0.0.0-20160606182133-d0e65e56babe/go.mod h1:aqO8z8wPrjkscevZJFVE1wXJrLpC5LtJG7fqLOsPb2U=
 github.com/envoyproxy/go-control-plane v0.6.9/go.mod h1:SBwIajubJHhxtWwsL9s8ss4safvEdbitLhGGK48rN6g=
@@ -123,7 +114,6 @@ github.com/foxcpp/go-imap-namespace v0.0.0-20200722130255-93092adf35f1 h1:B4zNQ2
 github.com/foxcpp/go-imap-namespace v0.0.0-20200722130255-93092adf35f1/go.mod h1:WJYkFIdxyljR/byiqcYMKUF4iFDej4CaIKe2JJrQxu8=
 github.com/foxcpp/go-imap-sql v0.4.1-0.20200823124337-2f57903a7ed0 h1:PWETJtfTn94l9zt1nqIZiFO0/hUQeBmptjtktqrau/Y=
 github.com/foxcpp/go-imap-sql v0.4.1-0.20200823124337-2f57903a7ed0/go.mod h1:1dHCAq3XRkYRwTDOtL/vCgvvQ13gLqNt2+nLjL1UHyk=
-github.com/foxcpp/go-mockdns v0.0.0-20191216195825-5eabd8dbfe1f h1:b/CFmrdqIGU6eV774xeaQwd1VfgiLuR/8jiY3LyLiMc=
 github.com/foxcpp/go-mockdns v0.0.0-20191216195825-5eabd8dbfe1f/go.mod h1:tPg4cp4nseejPd+UKxtCVQ2hUxNTZ7qQZJa7CLriIeo=
 github.com/foxcpp/go-mockdns v0.0.0-20200531120619-ae750bbf9d73 h1:rZE8KRqNsxz1Jqd782wLMK4FgZ8BKMwPCQjIEpA1bUs=
 github.com/foxcpp/go-mockdns v0.0.0-20200531120619-ae750bbf9d73/go.mod h1:tPg4cp4nseejPd+UKxtCVQ2hUxNTZ7qQZJa7CLriIeo=
@@ -142,7 +132,6 @@ github.com/go-logfmt/logfmt v0.3.0/go.mod h1:Qt1PoO58o5twSAckw1HlFXLmHsOX5/0LbT9
 github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=
 github.com/go-logfmt/logfmt v0.5.0/go.mod h1:wCYkCAKZfumFQihp8CzCvQ3paCTfi41vtzG1KdI/P7A=
 github.com/go-sql-driver/mysql v1.4.0/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
-github.com/go-sql-driver/mysql v1.4.1 h1:g24URVg0OFbNUTx9qqY1IRZ9D9z3iPyi5zKhQZpNwpA=
 github.com/go-sql-driver/mysql v1.4.1/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
 github.com/go-sql-driver/mysql v1.5.0 h1:ozyZYNQW3x3HtqT1jira07DN2PArx2v7/mN66gGcHOs=
 github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
@@ -156,14 +145,12 @@ github.com/golang/groupcache v0.0.0-20160516000752-02826c3e7903/go.mod h1:cIg4er
 github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
-github.com/golang/protobuf v1.3.1 h1:YF8+flBXS5eO826T4nzqPrxfhQThhXl0YzfuUPu4SBg=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.4.0-rc.1/go.mod h1:ceaxUfeHdC40wWswd/P6IGgMaK3YpKi5j83Wpe3EHw8=
 github.com/golang/protobuf v1.4.0-rc.1.0.20200221234624-67d41d38c208/go.mod h1:xKAWHe0F5eneWXFV3EuXVDTCmh+JuBKY0li0aMyXATA=
 github.com/golang/protobuf v1.4.0-rc.2/go.mod h1:LlEzMj4AhA7rCAGe4KMBDvJI+AwstrUpVNzEA03Pprs=
 github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0/go.mod h1:WU3c8KckQ9AFe+yFwt9sWVRKCVIyN9cPHBJSNnbL67w=
-github.com/golang/protobuf v1.4.0 h1:oOuy+ugB+P/kBdUnG5QaMXSIyJ1q38wWSojYCb3z5VQ=
 github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvqG2KuDX0=
 github.com/golang/protobuf v1.4.1/go.mod h1:U8fpvMrcmy5pZrNK1lt4xCsGvpyWQ/VVv6QDs8UjoX8=
 github.com/golang/protobuf v1.4.2 h1:+Z5KGCizgyZCbGh1KZqA0fcLLkwbsjIzS4aV2v7wJX0=
@@ -171,12 +158,9 @@ github.com/golang/protobuf v1.4.2/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw
 github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/google/btree v0.0.0-20180813153112-4030bb1f1f0c/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
-github.com/google/go-cmp v0.2.0 h1:+dTQ8DZQJz0Mb/HjFlkptS1FeQ4cWSnN941F8aEG4SQ=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
-github.com/google/go-cmp v0.3.1 h1:Xye71clBPdm5HgqGwUkwhbynsUJZhDbS20FvLhQ2izg=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
-github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.0 h1:/QaMHBdZ26BB3SSst0Iwl10Epc+xhTquomWX0oZEB6w=
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
@@ -234,7 +218,6 @@ github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+o
 github.com/klauspost/compress v1.10.5/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
 github.com/klauspost/compress v1.10.11 h1:K9z59aO18Aywg2b/WSgBaUX99mHy2BES18Cr5lBKZHk=
 github.com/klauspost/compress v1.10.11/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
-github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/konsorten/go-windows-terminal-sequences v1.0.3/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/kr/logfmt v0.0.0-20140226030751-b84e30acd515/go.mod h1:+0opPa2QZZtGFBFZlji/RkVcI2GknAs/DXo4wKdlNEc=
@@ -249,12 +232,10 @@ github.com/lib/pq v1.8.0/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/lightstep/lightstep-tracer-common/golang/gogo v0.0.0-20190605223551-bc2310a04743/go.mod h1:qklhhLq1aX+mtWk9cPHPzaBjWImj5ULL6C7HFJtXQMM=
 github.com/lightstep/lightstep-tracer-go v0.18.1/go.mod h1:jlF1pusYV4pidLvZ+XD0UBX0ZE6WURAspgAczcDHrL4=
 github.com/lyft/protoc-gen-validate v0.0.13/go.mod h1:XbGvPuh87YZc5TdIa2/I4pLk0QoUACkjt2znoq26NVQ=
-github.com/mailru/easyjson v0.7.1 h1:mdxE1MF9o53iCb2Ghj1VfWvh7ZOwHpnVG/xwXrV90U8=
 github.com/mailru/easyjson v0.7.1/go.mod h1:KAzv3t3aY1NaHWoQz1+4F1ccyAH66Jk7yos7ldAVICs=
 github.com/mailru/easyjson v0.7.6 h1:8yTIVnZgCoiM1TgqoeTl+LfU5Jg6/xL3QhGQnimLYnA=
 github.com/mailru/easyjson v0.7.6/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
 github.com/martinlindhe/base36 v0.0.0-20190418230009-7c6542dfbb41/go.mod h1:+AtEs8xrBpCeYgSLoY/aJ6Wf37jtBuR0s35750M27+8=
-github.com/martinlindhe/base36 v1.0.0 h1:eYsumTah144C0A8P1T/AVSUk5ZoLnhfYFM3OGQxB52A=
 github.com/martinlindhe/base36 v1.0.0/go.mod h1:+AtEs8xrBpCeYgSLoY/aJ6Wf37jtBuR0s35750M27+8=
 github.com/martinlindhe/base36 v1.1.0 h1:cIwvvwYse/0+1CkUPYH5ZvVIYG3JrILmQEIbLuar02Y=
 github.com/martinlindhe/base36 v1.1.0/go.mod h1:+AtEs8xrBpCeYgSLoY/aJ6Wf37jtBuR0s35750M27+8=
@@ -337,7 +318,6 @@ github.com/prometheus/client_model v0.2.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6T
 github.com/prometheus/common v0.2.0/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.4.1/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.7.0/go.mod h1:DjGbpBbp5NYNiECxcL/VnbXCCaQpKd3tt26CguLLsqA=
-github.com/prometheus/common v0.10.0 h1:RyRA7RzGXQZiW+tGMr7sxa85G1z0yOpM1qq5c8lNawc=
 github.com/prometheus/common v0.10.0/go.mod h1:Tlit/dnDKsSWFlCLTWaA1cyBgKHSMdTB80sz/V91rCo=
 github.com/prometheus/common v0.13.0 h1:vJlpe9wPgDRM1Z+7Wj3zUUjY1nr6/1jNKyl7llliccg=
 github.com/prometheus/common v0.13.0/go.mod h1:U+gB1OBLb1lF3O42bTCL+FK18tX9Oar16Clt/msog/s=
@@ -465,13 +445,11 @@ golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20191220142924-d4481acd189f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200615200032-f1bc736245b1 h1:ogLJMz+qpzav7lGMh10LMvAkM/fAoGlaiiHYiFYdm80=
 golang.org/x/sys v0.0.0-20200615200032-f1bc736245b1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200625212154-ddb9806d33ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200821140526-fda516888d29 h1:mNuhGagCf3lDDm5C0376C/sxh6V7fy9WbdEu/YDNA04=
 golang.org/x/sys v0.0.0-20200821140526-fda516888d29/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.3.3 h1:cokOdA+Jmi5PJGXLlLllQSgYigAEfHXJAERHVMaCc2k=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
@@ -522,7 +500,6 @@ google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLY
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
 google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=
 google.golang.org/protobuf v1.20.1-0.20200309200217-e05f789c0967/go.mod h1:A+miEFZTKqfCUM6K7xSMQL9OKL/b6hQv+e19PK+JZNE=
-google.golang.org/protobuf v1.21.0 h1:qdOKuR/EIArgaWNjetjgTzgVTAZ+S/WXVrq9HW9zimw=
 google.golang.org/protobuf v1.21.0/go.mod h1:47Nbq4nVaFHyn7ilMalzfO3qCViNmqZ2kzikPIcrTAo=
 google.golang.org/protobuf v1.22.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=

internal/smtpconn/smtpconn.go

@@ -34,6 +34,7 @@ import (
 	"io"
 	"net"
 	"runtime/trace"
+	"time"
 
 	"github.com/emersion/go-message/textproto"
 	"github.com/emersion/go-smtp"
@@ -52,6 +53,17 @@ type C struct {
 	// DialContext by New.
 	Dialer func(ctx context.Context, network, addr string) (net.Conn, error)
 
+	// Timeout for most session commands (EHLO, MAIL, RCPT, DATA, STARTTLS).
+	// Set to 5 mins by New.
+	CommandTimeout time.Duration
+
+	// Timeout for the initial TCP connection establishment.
+	ConnectTimeout time.Duration
+
+	// Timeout for the final dot. Set to 12 mins by New.
+	// (see go-smtp source for explanation of used defaults).
+	SubmissionTimeout time.Duration
+
 	// Hostname to sent in the EHLO/HELO command. Set to
 	// 'localhost.localdomain' by New. Expected to be encoded in ACE form.
 	Hostname string
@@ -75,9 +87,12 @@ type C struct {
 // with resonable default values.
 func New() *C {
 	return &C{
-		Dialer:    (&net.Dialer{}).DialContext,
+		Dialer:            (&net.Dialer{}).DialContext,
-		TLSConfig: &tls.Config{},
+		ConnectTimeout:    5 * time.Minute,
-		Hostname:  "localhost.localdomain",
+		CommandTimeout:    5 * time.Minute,
+		SubmissionTimeout: 12 * time.Minute,
+		TLSConfig:         &tls.Config{},
+		Hostname:          "localhost.localdomain",
 	}
 }
 
@@ -188,7 +203,10 @@ func (err TLSError) Unwrap() error {
 
 func (c *C) attemptConnect(ctx context.Context, lmtp bool, endp config.Endpoint, starttls bool, tlsConfig *tls.Config) (didTLS bool, cl *smtp.Client, err error) {
 	var conn net.Conn
-	conn, err = c.Dialer(ctx, endp.Network(), endp.Address())
+
+	dialCtx, cancel := context.WithTimeout(ctx, c.ConnectTimeout)
+	conn, err = c.Dialer(dialCtx, endp.Network(), endp.Address())
+	cancel()
 	if err != nil {
 		return false, nil, err
 	}
@@ -199,6 +217,7 @@ func (c *C) attemptConnect(ctx context.Context, lmtp bool, endp config.Endpoint,
 		conn = tls.Client(conn, cfg)
 	}
 
+	// This uses initial greeting timeout of 5 minutes (hardcoded).
 	if lmtp {
 		cl, err = smtp.NewClientLMTP(conn, endp.Host)
 	} else {
@@ -209,6 +228,9 @@ func (c *C) attemptConnect(ctx context.Context, lmtp bool, endp config.Endpoint,
 		return false, nil, err
 	}
 
+	cl.CommandTimeout = c.CommandTimeout
+	cl.SubmissionTimeout = c.SubmissionTimeout
+
 	// i18n: hostname is already expected to be in A-labels form.
 	if err := cl.Hello(c.Hostname); err != nil {
 		cl.Close()

internal/target/remote/connect.go

@@ -284,6 +284,15 @@ func (rd *remoteDelivery) newConn(ctx context.Context, domain string) (*mxConn,
 	conn.Log = rd.Log
 	conn.Hostname = rd.rt.hostname
 	conn.AddrInSMTPMsg = true
+	if rd.rt.connectTimeout != 0 {
+		conn.ConnectTimeout = rd.rt.connectTimeout
+	}
+	if rd.rt.commandTimeout != 0 {
+		conn.CommandTimeout = rd.rt.commandTimeout
+	}
+	if rd.rt.submissionTimeout != 0 {
+		conn.SubmissionTimeout = rd.rt.submissionTimeout
+	}
 
 	for _, p := range rd.policies {
 		p.PrepareDomain(ctx, domain)

internal/target/remote/remote.go

@@ -32,6 +32,7 @@ import (
 	"runtime/trace"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/emersion/go-message/textproto"
 	"github.com/foxcpp/maddy/framework/address"
@@ -76,6 +77,10 @@ type Target struct {
 	connReuseLimit int
 
 	Log log.Logger
+
+	connectTimeout    time.Duration
+	commandTimeout    time.Duration
+	submissionTimeout time.Duration
 }
 
 var _ module.DeliveryTarget = &Target{}
@@ -130,6 +135,9 @@ func (rt *Target) Init(cfg *config.Map) error {
 	cfg.Bool("requiretls_override", false, true, &rt.allowSecOverride)
 	cfg.Bool("relaxed_requiretls", false, true, &rt.relaxedREQUIRETLS)
 	cfg.Int("conn_reuse_limit", false, false, 10, &rt.connReuseLimit)
+	cfg.Duration("connect_timeout", false, false, 5*time.Minute, &rt.connectTimeout)
+	cfg.Duration("command_timeout", false, false, 5*time.Minute, &rt.commandTimeout)
+	cfg.Duration("submission_timeout", false, false, 5*time.Minute, &rt.submissionTimeout)
 
 	poolCfg := pool.Config{
 		MaxKeys:             20000,

internal/target/smtp/smtp_downstream.go

@@ -33,6 +33,7 @@ import (
 	"fmt"
 	"net"
 	"runtime/trace"
+	"time"
 
 	"github.com/emersion/go-message/textproto"
 	"github.com/emersion/go-smtp"
@@ -60,6 +61,10 @@ type Downstream struct {
 	saslFactory     saslClientFactory
 	tlsConfig       tls.Config
 
+	connectTimeout    time.Duration
+	commandTimeout    time.Duration
+	submissionTimeout time.Duration
+
 	log log.Logger
 }
 
@@ -102,6 +107,9 @@ func (u *Downstream) Init(cfg *config.Map) error {
 	cfg.Custom("tls_client", true, false, func() (interface{}, error) {
 		return tls.Config{}, nil
 	}, tls2.TLSClientBlock, &u.tlsConfig)
+	cfg.Duration("connect_timeout", false, false, 5*time.Minute, &u.connectTimeout)
+	cfg.Duration("command_timeout", false, false, 5*time.Minute, &u.commandTimeout)
+	cfg.Duration("submission_timeout", false, false, 5*time.Minute, &u.submissionTimeout)
 
 	if _, err := cfg.Process(); err != nil {
 		return err
@@ -188,6 +196,15 @@ func (d *delivery) connect(ctx context.Context) error {
 	conn.Log = d.log
 	conn.Hostname = d.u.hostname
 	conn.AddrInSMTPMsg = false
+	if d.u.connectTimeout != 0 {
+		conn.ConnectTimeout = d.u.connectTimeout
+	}
+	if d.u.commandTimeout != 0 {
+		conn.CommandTimeout = d.u.commandTimeout
+	}
+	if d.u.submissionTimeout != 0 {
+		conn.SubmissionTimeout = d.u.submissionTimeout
+	}
 
 	for _, endp := range d.u.endpoints {
 		var (