Re: [PATCH 3/9] port_fwd: Better parameterise procfs_scan_listen()

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, Nov 02, 2023 at 07:07:19PM +0100, Stefano Brivio wrote:
> On Thu,  5 Oct 2023 14:44:39 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > procfs_scan_listen() does some slightly clunky logic to deduce the fd it
> > wants to use, the path it wants to open and the state it's looking for
> > based on parameters for protocol, IP version and whether we're in the
> > namespace.
> > 
> > However, the caller already has to make choices based on similar parameters
> > so it can just pass in the things that procfs_scan_listen() needs directly.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> >  port_fwd.c | 53 +++++++++++++++++++++++------------------------------
> >  1 file changed, 23 insertions(+), 30 deletions(-)
> > 
> > diff --git a/port_fwd.c b/port_fwd.c
> > index 136a450..4b54877 100644
> > --- a/port_fwd.c
> > +++ b/port_fwd.c
> > @@ -23,39 +23,27 @@
> >  #include "passt.h"
> >  #include "lineread.h"
> >  
> > +#define UDP_LISTEN	0x07
> > +#define TCP_LISTEN	0x0a
> > +
> >  /**
> >   * procfs_scan_listen() - Set bits for listening TCP or UDP sockets from procfs
> > - * @proto:	IPPROTO_TCP or IPPROTO_UDP
> > - * @ip_version:	IP version, V4 or V6
> > - * @ns:		Use saved file descriptors for namespace if set
> > + * @fd:		Pointer to fd for relevant /proc/net file
> > + * @path:	Path to /proc/net file to open (if fd is -1)
> > + * @lstate:	Code for listening state to scan for
> >   * @map:	Bitmap where numbers of ports in listening state will be set
> >   * @exclude:	Bitmap of ports to exclude from setting (and clear)
> >   *
> >   * #syscalls:pasta lseek
> >   * #syscalls:pasta ppc64le:_llseek ppc64:_llseek armv6l:_llseek armv7l:_llseek
> >   */
> > -static void procfs_scan_listen(struct ctx *c, uint8_t proto, int ip_version,
> > -			       int ns, uint8_t *map, const uint8_t *exclude)
> > +static void procfs_scan_listen(int *fd, const char *path, unsigned int lstate,
> > +			       uint8_t *map, const uint8_t *exclude)
> >  {
> > -	char *path, *line;
> >  	struct lineread lr;
> >  	unsigned long port;
> >  	unsigned int state;
> > -	int *fd;
> > -
> > -	if (proto == IPPROTO_TCP) {
> > -		fd = &c->proc_net_tcp[ip_version][ns];
> > -		if (ip_version == V4)
> > -			path = "/proc/net/tcp";
> > -		else
> > -			path = "/proc/net/tcp6";
> > -	} else {
> > -		fd = &c->proc_net_udp[ip_version][ns];
> > -		if (ip_version == V4)
> > -			path = "/proc/net/udp";
> > -		else
> > -			path = "/proc/net/udp6";
> > -	}
> > +	char *line;
> >  
> >  	if (*fd != -1) {
> >  		if (lseek(*fd, 0, SEEK_SET)) {
> > @@ -74,8 +62,7 @@ static void procfs_scan_listen(struct ctx *c, uint8_t proto, int ip_version,
> >  			continue;
> >  
> >  		/* See enum in kernel's include/net/tcp_states.h */
> 
> This comment should now be moved before #define UDP_LISTEN and
> TCP_LISTEN, as it's not otherwise clear where they're coming from.

Good point, fixed.

> Given how late I'm reviewing all this, and that presumably you have a
> bunch of series/patches based on it, I'm also fine to apply this and
> patch it in a separate commit, or also fix this up on merge myself --
> let me know.
> 
> Same for the comments to the next patches/series.

Eh, I don't think the rebasing should be too hard, so I'm happy to
sort that out.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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