Must every packet have a creating socket? (was Re: Does a forwarded packet has a local socket with it?)

Must every packet have a creating socket? (was Re: Does a forwarded packet has a local socket with it?)

[Park Lee]

On Tue, 19 Apr 2005 at 08:26, Neil Horman wrote:
> Not sure what your asking here.  Asking "Does these 
> two sockets belong to local socket?" is a pretty 
> meaningless question, as the terminology is 
> nonsensical. All sockets have a protocol associated 
> with them (except raw sockets, but thats another 
> topic).  When you create a socket you associate it 
> with a protocol family (AF_INET, AF_INET6, 
> AF_NETLINK, AF_APPLETALK, etc), 
> a connection type (SOCK_STREAM for connection 
> oriented  protocols, SOCK_DGRAM for connection-less 
> protocols), and a protocol (IPPROTO_TCP, 
> IPPROTO_UDP, etc).  Depending on the family, type 
> and protocol you select, you can talk to different 
> systems/services.
>
> Does that answer your question?

Thanks a lot.

Can I think that every packet (e.g. IP packet) must
have a corresponding creating socket? (i.e. Must every
packet be created by a socket?) 
Is there any other way to originate a packet?

Thank you.

Best Regards,
Park Lee


		
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Re: Must every packet have a creating socket? (was Re: Does a forwarded packet has a local socket with it?)

[Rick Jones]

> Can I think that every packet (e.g. IP packet) must
> have a corresponding creating socket? (i.e. Must every
> packet be created by a socket?) 

No.  ICMP messages come to mind - although I _suppose_ that since those are in 
response to other traffic, you could claim it was in response to something sent 
from a "socket" or "endpoint" - depends on how far away you consider it to still 
be  from a socket.

> Is there any other way to originate a packet?


> 
> Thank you.
> 
> Best Regards,
> Park Lee
> 
> 
> 		
> __________________________________ 
> Do you Yahoo!? 
> Make Yahoo! your home page 
> http://www.yahoo.com/r/hs

Re: Must every packet have a creating socket?

[Andi Kleen]

Rick Jones <rick.jones2@hp.com> writes:

>> Can I think that every packet (e.g. IP packet) must
>> have a corresponding creating socket? (i.e. Must every
>> packet be created by a socket?)
>
> No.  ICMP messages come to mind - although I _suppose_ that since
> those are in response to other traffic, you could claim it was in
> response to something sent from a "socket" or "endpoint" - depends on
> how far away you consider it to still be  from a socket.

Actually Linux has kernel private sockets for ICMP.
Very old Linux didnt, but it required ugly special cases
in the transmit path, so it was removed.

-Andi