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port_fwd: Move automatic port forwarding code to port_fwd.[ch]

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The implementation of scanning /proc files to do automatic port forwarding
is a bit awkwardly split between procfs_scan_listen() in util.c,
get_bound_ports() and related functions in conf.c and the initial setup
code in conf().

Consolidate all of this into port_fwd.h, which already has some related
definitions, and a new port_fwd.c.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson
2023-11-03 13:22:56 +11:00
committed by Stefano Brivio
parent 26d86f1304
commit e90f2770ae
8 changed files with 185 additions and 153 deletions
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65
util.c
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@@ -28,7 +28,6 @@
#include "util.h"
#include "passt.h"
#include "packet.h"
#include "lineread.h"
#include "log.h"
#define IPV6_NH_OPT(nh) \
@@ -326,69 +325,7 @@ int bitmap_isset(const uint8_t *map, int bit)
return !!(*word & BITMAP_BIT(bit));
}
/**
* 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
* @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
*/
void procfs_scan_listen(struct ctx *c, uint8_t proto, int ip_version, int ns,
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";
}
if (*fd != -1) {
if (lseek(*fd, 0, SEEK_SET)) {
warn("lseek() failed on %s: %s", path, strerror(errno));
return;
}
} else if ((*fd = open(path, O_RDONLY | O_CLOEXEC)) < 0) {
return;
}
lineread_init(&lr, *fd);
lineread_get(&lr, &line); /* throw away header */
while (lineread_get(&lr, &line) > 0) {
/* NOLINTNEXTLINE(cert-err34-c): != 2 if conversion fails */
if (sscanf(line, "%*u: %*x:%lx %*x:%*x %x", &port, &state) != 2)
continue;
/* See enum in kernel's include/net/tcp_states.h */
if ((proto == IPPROTO_TCP && state != 0x0a) ||
(proto == IPPROTO_UDP && state != 0x07))
continue;
if (bitmap_isset(exclude, port))
bitmap_clear(map, port);
else
bitmap_set(map, port);
}
}
/**
/*
* ns_enter() - Enter configured user (unless already joined) and network ns
* @c: Execution context
*