mirror of https://github.com/hak5/openwrt.git
165 lines
6.1 KiB
Diff
165 lines
6.1 KiB
Diff
From 65f777e7f66b55239d935c1cf81bb5abc0f6c89f Mon Sep 17 00:00:00 2001
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From: Grinch <grinch79@users.sourceforge.net>
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Date: Sun, 16 Aug 2009 19:58:26 +0500
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Subject: [PATCH] Restrict igmp reports for downstream interfaces (wrt #2833339)
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atm all igmp membership reports are forwarded to the upstream interface.
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Unfortunately some ISP Providers restrict some multicast groups (esp. those
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that are defined as local link groups and that are not supposed to be
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forwarded to the wan, i.e 224.0.0.0/24). Therefore there should be some
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kind of black oder whitelisting.
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As whitelisting can be accomplished quite easy I wrote a litte patch, which
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is attached to this request.
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---
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doc/igmpproxy.conf.5.in | 19 +++++++++++++++++++
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src/config.c | 23 ++++++++++++++++++++++-
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src/igmpproxy.h | 1 +
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src/request.c | 20 ++++++++++++++++----
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4 files changed, 58 insertions(+), 5 deletions(-)
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diff --git a/doc/igmpproxy.conf.5.in b/doc/igmpproxy.conf.5.in
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index a4ea7d0..56efa22 100644
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--- a/doc/igmpproxy.conf.5.in
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+++ b/doc/igmpproxy.conf.5.in
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@@ -116,6 +116,25 @@ This is especially useful for the upstream interface, since the source for multi
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traffic is often from a remote location. Any number of altnet parameters can be specified.
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.RE
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+.B whitelist
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+.I networkaddr
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+.RS
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+Defines a whitelist for multicast groups. The network address must be in the following
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+format 'a.b.c.d/n'. If you want to allow one single group use a network mask of /32,
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+i.e. 'a.b.c.d/32'.
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+
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+By default all multicast groups are allowed on any downstream interface. If at least one
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+whitelist entry is defined, all igmp membership reports for not explicitly whitelisted
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+multicast groups will be ignored and therefore not be served by igmpproxy. This is especially
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+useful, if your provider does only allow a predefined set of multicast groups. These whitelists
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+are only obeyed by igmpproxy itself, they won't prevent any other igmp client running on the
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+same machine as igmpproxy from requesting 'unallowed' multicast groups.
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+
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+You may specify as many whitelist entries as needed. Although you should keep it as simple as
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+possible, as this list is parsed for every membership report and therefore this increases igmp
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+response times. Often used or large groups should be defined first, as parsing ends as soon as
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+a group matches an entry.
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+.RE
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.SH EXAMPLE
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## Enable quickleave
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diff --git a/src/config.c b/src/config.c
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index 5a96ce0..d72619f 100644
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--- a/src/config.c
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+++ b/src/config.c
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@@ -46,6 +46,9 @@ struct vifconfig {
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// Keep allowed nets for VIF.
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struct SubnetList* allowednets;
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+
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+ // Allowed Groups
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+ struct SubnetList* allowedgroups;
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// Next config in list...
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struct vifconfig* next;
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@@ -202,6 +205,8 @@ void configureVifs() {
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// Insert the configured nets...
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vifLast->next = confPtr->allowednets;
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+ Dp->allowedgroups = confPtr->allowedgroups;
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+
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break;
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}
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}
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@@ -215,7 +220,7 @@ void configureVifs() {
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*/
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struct vifconfig *parsePhyintToken() {
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struct vifconfig *tmpPtr;
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- struct SubnetList **anetPtr;
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+ struct SubnetList **anetPtr, **agrpPtr;
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char *token;
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short parseError = 0;
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@@ -239,6 +244,7 @@ struct vifconfig *parsePhyintToken() {
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tmpPtr->threshold = 1;
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tmpPtr->state = IF_STATE_DOWNSTREAM;
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tmpPtr->allowednets = NULL;
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+ tmpPtr->allowedgroups = NULL;
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// Make a copy of the token to store the IF name
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tmpPtr->name = strdup( token );
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@@ -248,6 +254,7 @@ struct vifconfig *parsePhyintToken() {
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// Set the altnet pointer to the allowednets pointer.
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anetPtr = &tmpPtr->allowednets;
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+ agrpPtr = &tmpPtr->allowedgroups;
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// Parse the rest of the config..
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token = nextConfigToken();
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@@ -266,6 +273,20 @@ struct vifconfig *parsePhyintToken() {
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anetPtr = &(*anetPtr)->next;
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}
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}
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+ else if(strcmp("whitelist", token)==0) {
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+ // Whitelist
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+ token = nextConfigToken();
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+ my_log(LOG_DEBUG, 0, "Config: IF: Got whitelist token %s.", token);
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+
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+ *agrpPtr = parseSubnetAddress(token);
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+ if(*agrpPtr == NULL) {
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+ parseError = 1;
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+ my_log(LOG_WARNING, 0, "Unable to parse subnet address.");
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+ break;
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+ } else {
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+ agrpPtr = &(*agrpPtr)->next;
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+ }
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+ }
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else if(strcmp("upstream", token)==0) {
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// Upstream
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my_log(LOG_DEBUG, 0, "Config: IF: Got upstream token.");
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diff --git a/src/igmpproxy.h b/src/igmpproxy.h
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index 4dabd1c..0de7791 100644
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--- a/src/igmpproxy.h
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+++ b/src/igmpproxy.h
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@@ -145,6 +145,7 @@ struct IfDesc {
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short Flags;
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short state;
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struct SubnetList* allowednets;
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+ struct SubnetList* allowedgroups;
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unsigned int robustness;
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unsigned char threshold; /* ttl limit */
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unsigned int ratelimit;
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diff --git a/src/request.c b/src/request.c
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index e3589f6..89b91de 100644
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--- a/src/request.c
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+++ b/src/request.c
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@@ -82,10 +82,22 @@ void acceptGroupReport(uint32_t src, uint32_t group, uint8_t type) {
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my_log(LOG_DEBUG, 0, "Should insert group %s (from: %s) to route table. Vif Ix : %d",
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inetFmt(group,s1), inetFmt(src,s2), sourceVif->index);
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- // The membership report was OK... Insert it into the route table..
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- insertRoute(group, sourceVif->index);
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-
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-
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+ // If we don't have a whitelist we insertRoute and done
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+ if(sourceVif->allowedgroups == NULL)
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+ {
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+ insertRoute(group, sourceVif->index);
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+ return;
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+ }
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+ // Check if this Request is legit on this interface
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+ struct SubnetList *sn;
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+ for(sn = sourceVif->allowedgroups; sn != NULL; sn = sn->next)
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+ if((group & sn->subnet_mask) == sn->subnet_addr)
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+ {
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+ // The membership report was OK... Insert it into the route table..
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+ insertRoute(group, sourceVif->index);
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+ return;
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+ }
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+ my_log(LOG_INFO, 0, "The group address %s may not be requested from this interface. Ignoring.", inetFmt(group, s1));
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} else {
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// Log the state of the interface the report was recieved on.
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my_log(LOG_INFO, 0, "Mebership report was recieved on %s. Ignoring.",
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--
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1.7.2.5
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