Basic PROXY protocol support for Squid-to-peer connections #281
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src/FwdState.cc
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| MemBuf mb; | ||
| mb.init(); | ||
| header.packInto(mb); |
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Yes, MemBuf::grow() asserts on overlfows. A lot of Squid code ignores that fact, and the default 2GB max_capacity value makes such assertions rare. I believe we can also ignore them just like, say, HttpHeader::packInto() does. It is a negative factor when it comes to SBuf-vs-MemBuf decision, but it is not a critical one.
For now, please continue to use MemBuf. We will revisit this decision when serialization API is finalized.
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I switched PROXY protocol header packing code to use new serialization API, but this sendProxyProtoHeaderIfNeeded() code still uses MemBuf for Comm::Write(), as I suggested earlier. I added a TODO to get rid of this deprecated MemBuf addition, but let's not change/improve that for now -- we have much bigger issues to solve!
src/proxyp/Header.cc
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| ProxyProtocol::Header::Header(const SBuf &ver, const Two::Command cmd): | ||
| version_(ver), | ||
| command_(cmd), | ||
| ignoreAddresses_(false) | ||
| {} | ||
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| void | ||
| ProxyProtocol::Header::packInto(MemBuf &mb) const |
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If this code survives, it should become:
| ProxyProtocol::Header::packInto(MemBuf &mb) const | |
| ProxyProtocol::Header::packInto(Packable &out) const |
However, for now, please continue to use MemBuf (and do not focus on the quality of this packing code -- as long as it produces the right serialization/bytes-on-the-wire). I am investigating a possible replacement/upgrade, but that will take some time, and there is no good reason to block your progress on that.
src/proxyp/Header.cc
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| // for TCP/UDP over IPv4, len = 12 | ||
| // for TCP/UDP over IPv6, len = 36 | ||
| const uint16_t len = 12; | ||
| mb.append(reinterpret_cast<const char *>(&len), sizeof(len)); |
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(AFAICT from the specs, we do not write the address length. It is determined by the address family (written earlier). See also: ProxyProtocol::Two::ParseAddresses().) Edit: I missed tokHeader.pstring16("header") that extracts these two bytes before calling ParseAddresses().
(BTW, ) this may not be the right way to write a 16-bit integer. See how Parser::BinaryTokenizer::uint16() handles endianness.
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I addressed this concern in branch commit 8c367fb.
| inline const auto & | ||
| Magic() | ||
| { | ||
| static const auto magic = new SBuf("PROXY", 5); |
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Please do not inline functions that use static variables, especially when we do not need to optimize their performance.
| namespace Two { | ||
| /// magic octet prefix for PROXY protocol version 2 | ||
| inline const auto & | ||
| Magic() |
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I think these declarations belong to proxyp/Elements.h (with definitions moved to Elements.cc).
This implementation is still untested. I also plan to remove the failed attempt at (hopefully premature) optimization to simplify further. This commit should fix PROXY protocol "tail" length packing. Also added code to pack TLVs. TLVs are currently absent, but ProxyProtocol::Header::pack() should not know that.
If we ever implement locking (removed in previous commit), this position will also help to "automatically" check the lock before any object updates. Also fixed method const-correctness.
src/proxyp/Header.cc
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| // for TCP/UDP over IPv4, len = 12 | ||
| // for TCP/UDP over IPv6, len = 36 | ||
| const uint16_t len = 12; | ||
| mb.append(reinterpret_cast<const char *>(&len), sizeof(len)); |
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I addressed this concern in branch commit 8c367fb.
src/FwdState.cc
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| MemBuf mb; | ||
| mb.init(); | ||
| header.packInto(mb); |
There was a problem hiding this comment.
I switched PROXY protocol header packing code to use new serialization API, but this sendProxyProtoHeaderIfNeeded() code still uses MemBuf for Comm::Write(), as I suggested earlier. I added a TODO to get rid of this deprecated MemBuf addition, but let's not change/improve that for now -- we have much bigger issues to solve!
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| BinaryPacker packer; | ||
| header.pack(packer); | ||
| const auto packed = packer.packed(); |
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When you update this code to generate the PROXY protocol header before opening a connection, please store it as SBuf. Convert to MemBuf only when it is time to write it (using the freshly opened connection).
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