Add args for sendmmsg events

[Biagio-Dipalma]

Motivation

Currently, the sendmmsg syscall is supported, but lacks arguments in both exit and entry events. I believe that adding parameters could significantly enhance the visibility of outbound connection events.

Feature

Add params to the sendmmsg events

[Andreagit97]

thank you for this! We will try to understand when to schedule this!

[oheifetz]

so basically you would like the sendmmsg to support an array of arguments where every argument is like what sendmsg does, right?

[oheifetz]

I can take it if no one has already started to add this support

[Andreagit97]

Yes we would like to have something similar to sendmsg syscall

	[PPME_SOCKET_SENDMSG_E] = {"sendmsg", EC_IO_WRITE | EC_SYSCALL, EF_USES_FD | EF_WRITES_TO_FD | EF_MODIFIES_STATE, 3, {{"fd", PT_FD, PF_DEC}, {"size", PT_UINT32, PF_DEC}, {"tuple", PT_SOCKTUPLE, PF_NA} } },
	[PPME_SOCKET_SENDMSG_X] = {"sendmsg", EC_IO_WRITE | EC_SYSCALL, EF_USES_FD | EF_WRITES_TO_FD | EF_MODIFIES_STATE, 2, {{"res", PT_ERRNO, PF_DEC}, {"data", PT_BYTEBUF, PF_NA} } },

but since there is no need to have some info in the enter event and others in the exit one, I would go with implementing all the info in the exit event, so something like

	[PPME_SOCKET_SENDMMSG_E] = {"sendmmsg", EC_IO_WRITE | EC_SYSCALL, EF_USES_FD, 0},
	[PPME_SOCKET_SENDMMSG_X] = {"sendmmsg", EC_IO_WRITE | EC_SYSCALL, EF_USES_FD, 5, {{"res", PT_ERRNO, PF_DEC}, {"fd", PT_FD, PF_DEC}, {"data", PT_BYTEBUF, PF_NA}, {"size", PT_UINT32, PF_DEC}, {"tuple", PT_SOCKTUPLE, PF_NA} } },

I can take it if no one has already started to add this support

Sure! thank you!

[oheifetz]

@Andreagit97 regarding your post above, you think that there is no need to push any data to ringbuf in enter since the only change between the enter and exit is the fact that on exit the msg_len changes and this may be important to user and on exit all other data can be inserted to ring?

[Andreagit97]

Yes, exactly. In the exit event, we have all syscalls parameters + the return value so it should be enough to collect everything in the exit event, since the enter event doesn't bring any additional value