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DHCPv6 Relay multivlan functionality support (#9178)
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Fix support for DHCPV6 Relay multi vlan functionality. Make sure the relayed packet is received at correct interface.

How I did it
Bind a socket to each vlan interface's global and link-local address.
Socket binded to global address is used for relaying data from client to server and receiving data from servers.
Socket binded to link-local address is used for relaying data received from server back to the client.
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@kellyyeh @qiluo-msft
kellyyeh authored and qiluo-msft committed Nov 15, 2021
1 parent 36f1a54 commit 2cbe6a7
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Showing 2 changed files with 62 additions and 75 deletions.
106 changes: 56 additions & 50 deletions src/dhcp6relay/src/relay.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -116,34 +116,6 @@ std::string toString(uint16_t count) {
return countValue;
}

/**
* @code bool is_addr_gua(in6_addr addr);
*
* @brief check if address is global
*
* @param addr ipv6 address
*
* @return bool
*/
bool is_addr_gua(in6_addr addr) {
auto masked = addr.__in6_u.__u6_addr8[0] & 0xe0;
return (masked ^ 0x20) == 0x00;
}

/**
* @code is_addr_link_local(in6_addr addr);
*
* @brief check if address is link_local
*
* @param addr ipv6 address
*
* @return bool
*/
bool is_addr_link_local(in6_addr addr) {
auto masked = ntohs(addr.__in6_u.__u6_addr16[0]) & 0xffc0;
return (masked ^ 0xfe80) == 0x0000;
}

/**
* @code const struct ether_header *parse_ether_frame(const uint8_t *buffer, const uint8_t **out_end);
*
Expand Down Expand Up @@ -356,19 +328,19 @@ void prepare_relay_config(relay_config *interface_config, int *local_sock, int f
while (ifa_tmp) {
if (ifa_tmp->ifa_addr->sa_family == AF_INET6) {
struct sockaddr_in6 *in6 = (struct sockaddr_in6*) ifa_tmp->ifa_addr;
if((strcmp(ifa_tmp->ifa_name, interface_config->interface.c_str()) == 0) && is_addr_gua(in6->sin6_addr)) {
if((strcmp(ifa_tmp->ifa_name, interface_config->interface.c_str()) == 0) && !IN6_IS_ADDR_LINKLOCAL(&in6->sin6_addr)) {
non_link_local = *in6;
break;
}
if((strcmp(ifa_tmp->ifa_name, interface_config->interface.c_str()) == 0) && is_addr_link_local(in6->sin6_addr)) {
if((strcmp(ifa_tmp->ifa_name, interface_config->interface.c_str()) == 0) && IN6_IS_ADDR_LINKLOCAL(&in6->sin6_addr)) {
link_local = *in6;
}
}
ifa_tmp = ifa_tmp->ifa_next;
}
freeifaddrs(ifa);

if(is_addr_gua(non_link_local.sin6_addr)) {
if(!IN6_IS_ADDR_LINKLOCAL(&non_link_local.sin6_addr)) {
interface_config->link_address = non_link_local;
}
else {
Expand All @@ -377,33 +349,63 @@ void prepare_relay_config(relay_config *interface_config, int *local_sock, int f
}

/**
* @code prepare_socket(int *local_sock);
* @code prepare_socket(int *local_sock, int *server_sock, relay_config *config, int index);
*
* @brief prepare L3 socket for sending
*
* @param local_sock pointer to socket to be prepared
* @param local_sock pointer to socket binded to global address for relaying client message to server and listening for server message
* @param server_sock pointer to socket binded to link_local address for relaying server message to client
* @param index scope id of interface
*
* @return none
*/
void prepare_socket(int *local_sock) {
int flag = 1;
void prepare_socket(int *local_sock, int *server_sock, relay_config *config, int index) {
struct ifaddrs *ifa, *ifa_tmp;
sockaddr_in6 addr;
sockaddr_in6 ll_addr;
memset(&addr, 0, sizeof(addr));
addr.sin6_family = AF_INET6;
addr.sin6_addr = in6addr_any;
addr.sin6_port = htons(RELAY_PORT);
memset(&ll_addr, 0, sizeof(ll_addr));

if ((*local_sock = socket(AF_INET6, SOCK_DGRAM, 0)) == -1) {
syslog(LOG_ERR, "socket: Failed to create socket\n");
}

if((setsockopt(*local_sock, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(flag))) == -1) {
syslog(LOG_ERR, "setsockopt: Unable to set socket option\n");
}
if ((*server_sock= socket(AF_INET6, SOCK_DGRAM, 0)) == -1) {
syslog(LOG_ERR, "socket: Failed to create socket\n");
}


if (getifaddrs(&ifa) == -1) {
syslog(LOG_WARNING, "getifaddrs: Unable to get network interfaces\n");
exit(1);
}

ifa_tmp = ifa;
while (ifa_tmp) {
if (ifa_tmp->ifa_addr->sa_family == AF_INET6) {
struct sockaddr_in6 *in6 = (struct sockaddr_in6*) ifa_tmp->ifa_addr;
if((strcmp(ifa_tmp->ifa_name, config->interface.c_str()) == 0) && !IN6_IS_ADDR_LINKLOCAL(&in6->sin6_addr)) {
in6->sin6_family = AF_INET6;
in6->sin6_port = htons(RELAY_PORT);
addr = *in6;
}
if((strcmp(ifa_tmp->ifa_name, config->interface.c_str()) == 0) && IN6_IS_ADDR_LINKLOCAL(&in6->sin6_addr)) {
in6->sin6_family = AF_INET6;
in6->sin6_port = htons(RELAY_PORT);
ll_addr = *in6;
}
}
ifa_tmp = ifa_tmp->ifa_next;
}
freeifaddrs(ifa);

if (bind(*local_sock, (sockaddr *)&addr, sizeof(addr)) == -1) {
syslog(LOG_ERR, "bind: Failed to bind to socket\n");
}
}

if (bind(*server_sock, (sockaddr *)&ll_addr, sizeof(addr)) == -1) {
syslog(LOG_ERR, "bind: Failed to bind to socket\n");
}
}


Expand Down Expand Up @@ -584,7 +586,7 @@ void server_callback(evutil_socket_t fd, short event, void *arg) {
std::string counterVlan = counter_table;
update_counter(config->db, counterVlan.append(config->interface), msg->msg_type);
if (msg->msg_type == DHCPv6_MESSAGE_TYPE_RELAY_REPL) {
relay_relay_reply(config->local_sock, message_buffer, data, config);
relay_relay_reply(config->server_sock, message_buffer, data, config);
}
}

Expand Down Expand Up @@ -681,11 +683,16 @@ void dhcp6relay_stop()
*/
void loop_relay(std::vector<relay_config> *vlans, swss::DBConnector *db) {
std::vector<int> sockets;

base = event_base_new();
if(base == NULL) {
syslog(LOG_ERR, "libevent: Failed to create base\n");
}

for(relay_config &vlan : *vlans) {
relay_config *config = &vlan;
int filter = 0;
int local_sock = 0;
int server_sock = 0;
const char *ifname = config->interface.c_str();
int index = if_nametoindex(ifname);
config->db = db;
Expand All @@ -694,10 +701,14 @@ void loop_relay(std::vector<relay_config> *vlans, swss::DBConnector *db) {
initialize_counter(config->db, counterVlan.append(config->interface));

filter = sock_open(index, &ether_relay_fprog);
prepare_socket(&local_sock, &server_sock, config, index);

config->local_sock = local_sock;
config->server_sock = server_sock;

prepare_socket(&local_sock);
sockets.push_back(filter);
sockets.push_back(local_sock);
sockets.push_back(server_sock);

prepare_relay_config(config, &local_sock, filter);

Expand All @@ -707,11 +718,6 @@ void loop_relay(std::vector<relay_config> *vlans, swss::DBConnector *db) {
evutil_make_listen_socket_reuseable(local_sock);
evutil_make_socket_nonblocking(local_sock);

base = event_base_new();
if(base == NULL) {
syslog(LOG_ERR, "libevent: Failed to create base\n");
}

listen_event = event_new(base, filter, EV_READ|EV_PERSIST, callback, config);
server_listen_event = event_new(base, local_sock, EV_READ|EV_PERSIST, server_callback, config);
if (listen_event == NULL || server_listen_event == NULL) {
Expand Down
31 changes: 6 additions & 25 deletions src/dhcp6relay/src/relay.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@ typedef enum

struct relay_config {
int local_sock;
int server_sock;
int filter;
sockaddr_in6 link_address;
swss::DBConnector *db;
Expand Down Expand Up @@ -90,15 +91,17 @@ struct linklayer_addr_option {
int sock_open(int ifindex, const struct sock_fprog *fprog);

/**
* @code prepare_socket(int *local_sock);
* @code prepare_socket(int *local_sock, int *server_sock, relay_config *config, int index);
*
* @brief prepare L3 socket for sending
*
* @param local_sock pointer to socket to be prepared
* @param local_sock pointer to socket binded to global address for relaying client message to server and listening for server message
* @param server_sock pointer to socket binded to link_local address for relaying server message to client
* @param index scope id of interface
*
* @return none
*/
void prepare_socket(int *local_sock);
void prepare_socket(int *local_sock, int *server_sock, relay_config *config, int index);

/**
* @code prepare_relay_config(relay_config *interface_config, int local_sock, int filter);
Expand Down Expand Up @@ -245,28 +248,6 @@ void update_counter(swss::DBConnector *db, std::string counterVlan, uint8_t msg_
*/
std::string toString(uint16_t count);

/**
* @code bool is_addr_gua(in6_addr addr);
*
* @brief check if address is global
*
* @param addr ipv6 address
*
* @return bool
*/
bool is_addr_gua(in6_addr addr);

/**
* @code is_addr_link_local(in6_addr addr);
*
* @brief check if address is link_local
*
* @param addr ipv6 address
*
* @return bool
*/
bool is_addr_link_local(in6_addr addr);

/**
* @code const struct ether_header *parse_ether_frame(const uint8_t *buffer, const uint8_t **out_end);
*
Expand Down

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