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207 bytes removed ,  21:14, 14 May 2013
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Currently we support Unix socket of all kinds, UDP both IPv4 and IPv6 and TCP in Listen and (!) [[TCP connection|Established states]].
 
Currently we support Unix socket of all kinds, UDP both IPv4 and IPv6 and TCP in Listen and (!) [[TCP connection|Established states]].
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The cpt part uses the sock_diag engine that was merged to Dave recently to
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The cpt part uses the sock_diag engine to collect extended information about socket. Then it drains sockets from the target tasks using SCM_RIGHTS sending.
collect sockets. Then it dumps sockets by checking the filesystem ID of a
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failed-to-open through /proc/pid/fd descriptors (sockets do not allow for
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such tricks with opens through proc) against SOCKFS_TYPE.
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The restore part is more tricky. Listen sockets are just restored, this is simple.
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The restore part of Unix sockets is the most tricky part. Listen sockets are just restored, this is simple.
 
Connected sockets are restored like this:
 
Connected sockets are restored like this:
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# ... all listening sockets call accept() and ... dup2 the new fd into the accepting end.
 
# ... all listening sockets call accept() and ... dup2 the new fd into the accepting end.
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There's a problem with this approach -- socket names are not preserved, but
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There's a problem with this approach -- socket names are not preserved, but looking into our OpenVZ implementation I think this is OK for existing apps.
looking into our OpenVZ implementation I think this is OK for existing apps.
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=== What should be done next ===
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* socket filter (SK_ATTACH_FILTER)
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* various (ip/tcp level) sockoptions
      
[[Category:Under the hood]]
 
[[Category:Under the hood]]

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