From b553a6b13c68cb72addde48281abe3f3b46e16a4 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Sun, 21 Feb 2016 14:11:34 +0100 Subject: sd-lldp: filter out LLDP messages coming from our own MAC address Let's not get confused should we be connected to some bridge that mirrors back our packets. --- src/basic/ether-addr-util.c | 23 +++++++++++++++++++++++ src/basic/ether-addr-util.h | 5 ++++- src/libsystemd-network/lldp-internal.h | 2 ++ src/libsystemd-network/sd-lldp.c | 21 +++++++++++++++++++++ src/network/networkd-link.c | 4 ++++ src/systemd/sd-lldp.h | 1 + 6 files changed, 55 insertions(+), 1 deletion(-) diff --git a/src/basic/ether-addr-util.c b/src/basic/ether-addr-util.c index ded6d31f4b..d2c030903b 100644 --- a/src/basic/ether-addr-util.c +++ b/src/basic/ether-addr-util.c @@ -42,3 +42,26 @@ char* ether_addr_to_string(const struct ether_addr *addr, char buffer[ETHER_ADDR return buffer; } + +bool ether_addr_is_null(const struct ether_addr *addr) { + assert(addr); + + return addr->ether_addr_octet[0] == 0 && + addr->ether_addr_octet[1] == 0 && + addr->ether_addr_octet[2] == 0 && + addr->ether_addr_octet[3] == 0 && + addr->ether_addr_octet[4] == 0 && + addr->ether_addr_octet[5] == 0; +} + +bool ether_addr_equal(const struct ether_addr *a, const struct ether_addr *b) { + assert(a); + assert(b); + + return a->ether_addr_octet[0] == b->ether_addr_octet[0] && + a->ether_addr_octet[1] == b->ether_addr_octet[1] && + a->ether_addr_octet[2] == b->ether_addr_octet[2] && + a->ether_addr_octet[3] == b->ether_addr_octet[3] && + a->ether_addr_octet[4] == b->ether_addr_octet[4] && + a->ether_addr_octet[5] == b->ether_addr_octet[5]; +} diff --git a/src/basic/ether-addr-util.h b/src/basic/ether-addr-util.h index 4487149efd..00c5159fe8 100644 --- a/src/basic/ether-addr-util.h +++ b/src/basic/ether-addr-util.h @@ -20,10 +20,13 @@ ***/ #include +#include #define ETHER_ADDR_FORMAT_STR "%02X%02X%02X%02X%02X%02X" #define ETHER_ADDR_FORMAT_VAL(x) (x).ether_addr_octet[0], (x).ether_addr_octet[1], (x).ether_addr_octet[2], (x).ether_addr_octet[3], (x).ether_addr_octet[4], (x).ether_addr_octet[5] #define ETHER_ADDR_TO_STRING_MAX (3*6) - char* ether_addr_to_string(const struct ether_addr *addr, char buffer[ETHER_ADDR_TO_STRING_MAX]); + +bool ether_addr_is_null(const struct ether_addr *addr); +bool ether_addr_equal(const struct ether_addr *a, const struct ether_addr *b); diff --git a/src/libsystemd-network/lldp-internal.h b/src/libsystemd-network/lldp-internal.h index 279975b5c2..7592bc4305 100644 --- a/src/libsystemd-network/lldp-internal.h +++ b/src/libsystemd-network/lldp-internal.h @@ -45,6 +45,8 @@ struct sd_lldp { void *userdata; uint16_t capability_mask; + + struct ether_addr filter_address; }; #define log_lldp_errno(error, fmt, ...) log_internal(LOG_DEBUG, error, __FILE__, __LINE__, __func__, "LLDP: " fmt, ##__VA_ARGS__) diff --git a/src/libsystemd-network/sd-lldp.c b/src/libsystemd-network/sd-lldp.c index 65cfa4e184..3af6133a4e 100644 --- a/src/libsystemd-network/sd-lldp.c +++ b/src/libsystemd-network/sd-lldp.c @@ -28,6 +28,7 @@ #include "lldp-neighbor.h" #include "lldp-network.h" #include "socket-util.h" +#include "ether-addr-util.h" #define LLDP_DEFAULT_NEIGHBORS_MAX 128U @@ -99,6 +100,11 @@ static int lldp_add_neighbor(sd_lldp *lldp, sd_lldp_neighbor *n) { if (n->ttl <= 0) return changed; + /* Filter out the filter address */ + if (!ether_addr_is_null(&lldp->filter_address) && + ether_addr_equal(&lldp->filter_address, &n->source_address)) + return changed; + /* Only add if the neighbor has a capability we are interested in. Note that we also store all neighbors with * no caps field set. */ if (n->has_capabilities && @@ -438,3 +444,18 @@ _public_ int sd_lldp_match_capabilities(sd_lldp *lldp, uint16_t mask) { return 0; } + +_public_ int sd_lldp_set_filter_address(sd_lldp *lldp, const struct ether_addr *addr) { + assert_return(lldp, -EINVAL); + + /* In order to deal nicely with bridges that send back our own packets, allow one address to be filtered, so + * that our own can be filtered out here. */ + + if (!addr) { + zero(lldp->filter_address); + return 0; + } + + lldp->filter_address = *addr; + return 0; +} diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c index 5c3e45fb3c..2bc6e3c842 100644 --- a/src/network/networkd-link.c +++ b/src/network/networkd-link.c @@ -2203,6 +2203,10 @@ static int link_configure(Link *link) { if (r < 0) return r; + r = sd_lldp_set_filter_address(link->lldp, &link->mac); + if (r < 0) + return r; + r = sd_lldp_attach_event(link->lldp, NULL, 0); if (r < 0) return r; diff --git a/src/systemd/sd-lldp.h b/src/systemd/sd-lldp.h index 11b89258ed..2ee32a534c 100644 --- a/src/systemd/sd-lldp.h +++ b/src/systemd/sd-lldp.h @@ -49,6 +49,7 @@ int sd_lldp_set_callback(sd_lldp *lldp, sd_lldp_callback_t cb, void *userdata); /* Controls how much and what to store in the neighbors database */ int sd_lldp_set_neighbors_max(sd_lldp *lldp, uint64_t n); int sd_lldp_match_capabilities(sd_lldp *lldp, uint16_t mask); +int sd_lldp_set_filter_address(sd_lldp *lldp, const struct ether_addr *address); int sd_lldp_get_neighbors(sd_lldp *lldp, sd_lldp_neighbor ***neighbors); -- cgit v1.2.3-54-g00ecf