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Clarify semantics of c->v4 and c->v6 variables

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The v4 and v6 fields of the context structure can be confusing, because
they change meaning part way through the code:  Before conf_ip(), they are
booleans which indicate whether the -4 or -6 options have been given.
After conf_ip() they are DISABLED|ENABLED|PROBE enums which indicate
whether the IP version is available (which means both that it was allowed
on the command line and we were able to configure it).  The PROBE variant
of the enum is only used locally within conf_ip() and since recent changes
there it no longer has a real purpose different from ENABLED.

Simplify this all by making the context fields always just a boolean
indicating the availability of the IP version.  They both default to 1, but
can be set to 0 by either command line options or configuration failures.
We use some local variables in conf() for tracking the state of the command
line options on their own.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Minor coding style fix in conf.c]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2022-07-22 15:31:16 +10:00 committed by Stefano Brivio
parent 4bc883aeab
commit c984ee5afd
2 changed files with 20 additions and 45 deletions
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59
conf.c
View file

@ -26,6 +26,7 @@
#include <pwd.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <syslog.h>
#include <time.h>
@ -615,40 +616,25 @@ static int conf_ns_opt(struct ctx *c,
*/
static void conf_ip(struct ctx *c)
{
int v4, v6;
if (c->v4) {
c->v4 = IP_VERSION_ENABLED;
v4 = IP_VERSION_PROBE;
v6 = c->v6 = IP_VERSION_DISABLED;
} else if (c->v6) {
c->v6 = IP_VERSION_ENABLED;
v6 = IP_VERSION_PROBE;
v4 = c->v4 = IP_VERSION_DISABLED;
} else {
c->v4 = c->v6 = IP_VERSION_ENABLED;
v4 = v6 = IP_VERSION_PROBE;
}
if (v4 != IP_VERSION_DISABLED) {
if (!c->ifi4)
c->ifi4 = nl_get_ext_if(AF_INET);
if (!c->ifi4) {
warn("No external routable interface for IPv4");
v4 = IP_VERSION_DISABLED;
c->v4 = 0;
}
}
if (v6 != IP_VERSION_DISABLED) {
if (c->v6) {
if (!c->ifi6)
c->ifi6 = nl_get_ext_if(AF_INET6);
if (!c->ifi6) {
warn("No external routable interface for IPv6");
v6 = IP_VERSION_DISABLED;
c->v6 = 0;
}
}
if (v4 != IP_VERSION_DISABLED) {
if (c->v4) {
if (!c->gw4)
nl_route(0, c->ifi4, AF_INET, &c->gw4);
@ -676,7 +662,7 @@ static void conf_ip(struct ctx *c)
nl_link(0, c->ifi4, c->mac, 0, 0);
}
if (v6 != IP_VERSION_DISABLED) {
if (c->v6) {
int prefix_len = 0;
if (IN6_IS_ADDR_UNSPECIFIED(&c->gw6))
@ -694,25 +680,18 @@ static void conf_ip(struct ctx *c)
}
if (!c->gw4 || !c->addr4 || MAC_IS_ZERO(c->mac))
v4 = IP_VERSION_DISABLED;
else
v4 = IP_VERSION_ENABLED;
c->v4 = 0;
if (IN6_IS_ADDR_UNSPECIFIED(&c->gw6) ||
IN6_IS_ADDR_UNSPECIFIED(&c->addr6) ||
IN6_IS_ADDR_UNSPECIFIED(&c->addr6_ll) ||
MAC_IS_ZERO(c->mac))
v6 = IP_VERSION_DISABLED;
else
v6 = IP_VERSION_ENABLED;
c->v6 = 0;
if ((v4 == IP_VERSION_DISABLED) && (v6 == IP_VERSION_DISABLED)) {
if (!c->v4 && !c->v6) {
err("External interface not usable");
exit(EXIT_FAILURE);
}
c->v4 = v4;
c->v6 = v6;
}
/**
@ -1054,8 +1033,8 @@ void conf(struct ctx *c, int argc, char **argv)
{"no-ndp", no_argument, &c->no_ndp, 1 },
{"no-ra", no_argument, &c->no_ra, 1 },
{"no-map-gw", no_argument, &c->no_map_gw, 1 },
{"ipv4-only", no_argument, &c->v4, '4' },
{"ipv6-only", no_argument, &c->v6, '6' },
{"ipv4-only", no_argument, NULL, '4' },
{"ipv6-only", no_argument, NULL, '6' },
{"tcp-ports", required_argument, NULL, 't' },
{"udp-ports", required_argument, NULL, 'u' },
{"tcp-ns", required_argument, NULL, 'T' },
@ -1079,6 +1058,7 @@ void conf(struct ctx *c, int argc, char **argv)
char nsdir[PATH_MAX] = { 0 }, userns[PATH_MAX] = { 0 };
enum conf_port_type tcp_tap = 0, tcp_init = 0;
enum conf_port_type udp_tap = 0, udp_init = 0;
bool v4_only = false, v6_only = false;
struct fqdn *dnss = c->dns_search;
struct in6_addr *dns6 = c->dns6;
int name, ret, mask, b, i;
@ -1474,10 +1454,10 @@ void conf(struct ctx *c, int argc, char **argv)
usage(argv[0]);
break;
case '4':
c->v4 = 1;
v4_only = true;
break;
case '6':
c->v6 = 1;
v6_only = true;
break;
case 't':
case 'u':
@ -1508,11 +1488,6 @@ void conf(struct ctx *c, int argc, char **argv)
usage(argv[0]);
}
if (c->v4 && c->v6) {
err("Options ipv4-only and ipv6-only are mutually exclusive");
usage(argv[0]);
}
if (c->pasta_conf_ns)
c->no_ra = 1;
@ -1524,6 +1499,12 @@ void conf(struct ctx *c, int argc, char **argv)
exit(EXIT_FAILURE);
}
if (v4_only && v6_only) {
err("Options ipv4-only and ipv6-only are mutually exclusive");
usage(argv[0]);
}
c->v4 = !v6_only;
c->v6 = !v4_only;
conf_ip(c);
/* Now we can process port configuration options */

6
util.h
View file

@ -74,12 +74,6 @@ void trace_init(int enable);
#define V6 1
#define IP_VERSIONS 2
enum {
IP_VERSION_DISABLED = 0,
IP_VERSION_ENABLED,
IP_VERSION_PROBE,
};
#define ARRAY_SIZE(a) ((int)(sizeof(a) / sizeof((a)[0])))
#define IN_INTERVAL(a, b, x) ((x) >= (a) && (x) <= (b))