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Fix #36: major refactor of how vifs are probed & installed
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This patch breaks out interface configuration from the config file
parser to ensure mrouted does not exhaust all available kernel vifs
before it knows what the user wants.

 - config_vifs_from_kernel() now creates a linked list of uvif's
   prepared to installed, with all available interface flags
 - config_vifs_from_file() now interacts with the new linked list
   disabling all interfaces with `no phyint` and enabling them
   on by one means is done before ...
 - config_vifs_correlate() runs.  It's only task is to take the
   logical sum of probed interface (in the order provided by the
   getifaddrs() function, or the order in the config file) and
   populate the old uvifs[] array and install the vifs in kernel

Signed-off-by: Joachim Wiberg <[email protected]>
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@troglobit
troglobit committed Sep 28, 2020
1 parent f87beee commit 22068c0
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Showing 4 changed files with 260 additions and 170 deletions.
171 changes: 44 additions & 127 deletions src/cfparse.y
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Original file line number Diff line number Diff line change
Expand Up @@ -20,8 +20,6 @@ static void warn(const char *fmt, ...);
static void yyerror(char *s);
static char *next_word(void);
static int yylex(void);
static uint32_t valid_if(char *s);
static const char *ifconfaddr(uint32_t addr);
int yyparse(void);

static FILE *fp;
Expand Down Expand Up @@ -100,83 +98,50 @@ stmts : /* Empty */
;

stmt : error
| NO PHYINT
{
vifi_t vifi;

for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v)
v->uv_flags |= VIFF_DISABLED;
}
| NO PHYINT { config_set_ifflag(VIFF_DISABLED); }
| PHYINT interface
{
vifi_t vifi;

state++;

if (order)
fatal("phyints must appear before tunnels");

for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
if (!(v->uv_flags & VIFF_TUNNEL) && $2 == v->uv_lcl_addr)
break;
}

if (vifi == numvifs) {
if ($2)
warn("phyint %s not available, continuing ...", inet_fmt($2, s1, sizeof(s1)));
v = config_find_ifaddr($2);
if (!v) {
warn("phyint %s not available, continuing ...",
inet_fmt($2, s1, sizeof(s1)));
v = &scrap;
}
}
ifmods
| TUNNEL interface addrname
{
const char *ifname;
struct ifreq ffr;
vifi_t vifi;

order++;

ifname = ifconfaddr($2);
if (ifname == 0)
fatal("Tunnel local address %s is not mine", inet_fmt($2, s1, sizeof(s1)));

if (((ntohl($2) & IN_CLASSA_NET) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET)
fatal("Tunnel local address %s is a loopback address", inet_fmt($2, s1, sizeof(s1)));

if (ifconfaddr($3) != NULL)
fatal("Tunnel remote address %s is one of mine", inet_fmt($3, s1, sizeof(s1)));

for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
if (v->uv_flags & VIFF_TUNNEL) {
if ($3 == v->uv_rmt_addr)
fatal("Duplicate tunnel to %s",
inet_fmt($3, s1, sizeof(s1)));
} else if (!(v->uv_flags & VIFF_DISABLED)) {
if (($3 & v->uv_subnetmask) == v->uv_subnet)
fatal("Unnecessary tunnel to %s, same subnet as vif %d (%s)",
inet_fmt($3, s1, sizeof(s1)), vifi, v->uv_name);
v = config_init_tunnel($2, $3, rexmit | noflood);
if (!v) {
switch (errno) {
case ENOENT:
fatal("Tunnel local address %s is not mine", inet_fmt($2, s1, sizeof(s1)));
break;
case ENONET:
fatal("Tunnel local address %s is a loopback address",
inet_fmt($2, s1, sizeof(s1)));
break;
case EADDRINUSE:
fatal("Tunnel remote address %s is one of mine",
inet_fmt($3, s1, sizeof(s1)));
break;
case EEXIST:
fatal("Duplicate tunnel to %s",
inet_fmt($3, s1, sizeof(s1)));
break;
default:
/* Log file and line number at least */
fatal("");
break;
}
}

if (numvifs == MAXVIFS)
fatal("too many vifs");

strlcpy(ffr.ifr_name, ifname, sizeof(ffr.ifr_name));
if (ioctl(udp_socket, SIOCGIFFLAGS, (char *)&ffr)<0)
fatal("ioctl SIOCGIFFLAGS on %s", ffr.ifr_name);

v = &uvifs[numvifs];
zero_vif(v, 1);
v->uv_flags = VIFF_TUNNEL | rexmit | noflood;
v->uv_flags |= VIFF_OTUNNEL; /* XXX */
v->uv_lcl_addr = $2;
v->uv_rmt_addr = $3;
v->uv_dst_addr = $3;
strlcpy(v->uv_name, ffr.ifr_name, sizeof(v->uv_name));

if (!(ffr.ifr_flags & IFF_UP)) {
v->uv_flags |= VIFF_DOWN;
vifs_down = TRUE;
v = &scrap;
}
}
tunnelmods
Expand Down Expand Up @@ -231,11 +196,8 @@ stmt : error
*/
| NOFLOOD
{
vifi_t vifi;

noflood = VIFF_NOFLOOD;
for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v)
v->uv_flags |= VIFF_NOFLOOD;
config_set_ifflag(VIFF_NOFLOOD);
}
/*
* Turn on prune retransmission on all interfaces.
Expand All @@ -244,10 +206,7 @@ stmt : error
*/
| REXMIT_PRUNES
{
vifi_t vifi;

for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v)
v->uv_flags |= VIFF_REXMIT_PRUNES;
config_set_ifflag(VIFF_REXMIT_PRUNES);
}
/*
* If true, do as above. If false, no need to turn
Expand All @@ -256,14 +215,10 @@ stmt : error
*/
| REXMIT_PRUNES BOOLEAN
{
if ($2) {
vifi_t vifi;

for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v)
v->uv_flags |= VIFF_REXMIT_PRUNES;
} else {
if ($2)
config_set_ifflag(VIFF_REXMIT_PRUNES);
else
rexmit = 0;
}
}
| NAME STRING boundary
{
Expand Down Expand Up @@ -575,9 +530,18 @@ interface: ADDR
}
| STRING
{
$$ = valid_if($1);
if ($$ == 0)
struct uvif *v;

/*
* Looks a little weird, but the orig. code was based around
* the addresses being used to identify interfaces.
*/
v = config_find_ifname($1);
if (!v) {
warn("phyint %s not available, continuing ...", $1);
$$ = 0;
} else
$$ = v->uv_lcl_addr;
}
;

Expand Down Expand Up @@ -894,53 +858,6 @@ void config_vifs_from_file(void)
fclose(fp);
}

static uint32_t valid_if(char *s)
{
struct uvif *v;
vifi_t vifi;

if (!s)
return 0;

for (vifi = 0, v = uvifs; vifi < numvifs; vifi++, v++) {
if (!strcmp(v->uv_name, s))
return v->uv_lcl_addr;
}

return 0;
}

static const char *ifconfaddr(uint32_t addr)
{
struct ifaddrs *ifap, *ifa;
static char buf[IFNAMSIZ];
char *ifname = NULL;

if (getifaddrs(&ifap) != 0)
return NULL;

for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
struct sockaddr_in *sin;

if (!ifa->ifa_addr)
continue;
if (ifa->ifa_addr->sa_family != AF_INET)
continue;

sin = (struct sockaddr_in *)ifa->ifa_addr;
if (sin->sin_addr.s_addr != addr)
continue;

strlcpy(buf, ifa->ifa_name, sizeof(buf));
ifname = buf;
break;
}

freeifaddrs(ifap);

return ifname;
}

/**
* Local Variables:
* indent-tabs-mode: t
Expand Down
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