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[dhcpmon] Open different socket for dual tor to enable interface filtering (#11201)

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This commit is contained in:
kellyyeh 2022-07-25 14:43:06 -07:00 committed by Qi Luo
parent 6c2f99a327
commit a2e0542356
9 changed files with 143 additions and 38 deletions
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1
rules/dhcpmon.mk
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@ -4,6 +4,7 @@ SONIC_DHCPMON_VERSION = 1.0.0-0
SONIC_DHCPMON_PKG_NAME = dhcpmon
SONIC_DHCPMON = sonic-$(SONIC_DHCPMON_PKG_NAME)_$(SONIC_DHCPMON_VERSION)_$(CONFIGURED_ARCH).deb
$(SONIC_DHCPMON)_DEPENDS = $(LIBSWSSCOMMON) $(LIBHIREDIS) $(LIBSWSSCOMMON_DEV) $(LIBHIREDIS_DEV)
$(SONIC_DHCPMON)_SRC_PATH = $(SRC_PATH)/$(SONIC_DHCPMON_PKG_NAME)
SONIC_DPKG_DEBS += $(SONIC_DHCPMON)

5
src/dhcpmon/Makefile
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@ -2,8 +2,9 @@ RM := rm -rf
DHCPMON_TARGET := dhcpmon
CP := cp
MKDIR := mkdir
CC := gcc
CC := g++
MV := mv
PWD := $(shell pwd)
# All of the sources participating in the build are defined here
-include src/subdir.mk
@ -23,7 +24,7 @@ all: sonic-dhcpmon
# Tool invocations
sonic-dhcpmon: $(OBJS) $(USER_OBJS)
@echo 'Building target: $@'
@echo 'Invoking: GCC C Linker'
@echo 'Invoking: G++ C Linker'
$(CC) -o "$(DHCPMON_TARGET)" $(OBJS) $(USER_OBJS) $(LIBS)
@echo 'Finished building target: $@'
@echo ' '

2
src/dhcpmon/objects.mk
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@ -1,4 +1,4 @@
USER_OBJS :=
LIBS := -levent -lexplain
LIBS := -levent -lexplain -lswsscommon -pthread -lboost_thread -lboost_system -lhiredis

150
src/dhcpmon/src/dhcp_device.c → src/dhcpmon/src/dhcp_device.cpp
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@ -21,6 +21,8 @@
#include <libexplain/ioctl.h>
#include <linux/filter.h>
#include <netpacket/packet.h>
#include "subscriberstatetable.h"
#include "select.h"
#include "dhcp_device.h"
@ -49,34 +51,42 @@
#define OP_JSET (BPF_JMP | BPF_JSET | BPF_K) /** bpf jset */
#define OP_LDXB (BPF_LDX | BPF_B | BPF_MSH) /** bpf ldxb */
std::shared_ptr<swss::DBConnector> mStateDbPtr = std::make_shared<swss::DBConnector> ("STATE_DB", 0);
std::shared_ptr<swss::Table> mStateDbMuxTablePtr = std::make_shared<swss::Table> (
mStateDbPtr.get(), "HW_MUX_CABLE_TABLE"
);
swss::DBConnector configDb("CONFIG_DB", 0);
/** Berkeley Packet Filter program for "udp and (port 67 or port 68)".
* This program is obtained using the following command tcpdump:
* `tcpdump -dd "udp and (port 67 or port 68)"`
* `tcpdump -dd "inbound and udp and (port 67 or port 68)"`
*/
static struct sock_filter dhcp_bpf_code[] = {
{.code = OP_LDHA, .jt = 0, .jf = 0, .k = 0x0000000c}, // (000) ldh [12]
{.code = OP_JEQ, .jt = 0, .jf = 7, .k = 0x000086dd}, // (001) jeq #0x86dd jt 2 jf 9
{.code = OP_LDB, .jt = 0, .jf = 0, .k = 0x00000014}, // (002) ldb [20]
{.code = OP_JEQ, .jt = 0, .jf = 18, .k = 0x00000011}, // (003) jeq #0x11 jt 4 jf 22
{.code = OP_LDHA, .jt = 0, .jf = 0, .k = 0x00000036}, // (004) ldh [54]
{.code = OP_JEQ, .jt = 15, .jf = 0, .k = 0x00000043}, // (005) jeq #0x43 jt 21 jf 6
{.code = OP_JEQ, .jt = 14, .jf = 0, .k = 0x00000044}, // (006) jeq #0x44 jt 21 jf 7
{.code = OP_LDHA, .jt = 0, .jf = 0, .k = 0x00000038}, // (007) ldh [56]
{.code = OP_JEQ, .jt = 12, .jf = 11, .k = 0x00000043}, // (008) jeq #0x43 jt 21 jf 20
{.code = OP_JEQ, .jt = 0, .jf = 12, .k = 0x00000800}, // (009) jeq #0x800 jt 10 jf 22
{.code = OP_LDB, .jt = 0, .jf = 0, .k = 0x00000017}, // (010) ldb [23]
{.code = OP_JEQ, .jt = 0, .jf = 10, .k = 0x00000011}, // (011) jeq #0x11 jt 12 jf 22
{.code = OP_LDHA, .jt = 0, .jf = 0, .k = 0x00000014}, // (012) ldh [20]
{.code = OP_JSET, .jt = 8, .jf = 0, .k = 0x00001fff}, // (013) jset #0x1fff jt 22 jf 14
{.code = OP_LDXB, .jt = 0, .jf = 0, .k = 0x0000000e}, // (014) ldxb 4*([14]&0xf)
{.code = OP_LDHI, .jt = 0, .jf = 0, .k = 0x0000000e}, // (015) ldh [x + 14]
{.code = OP_JEQ, .jt = 4, .jf = 0, .k = 0x00000043}, // (016) jeq #0x43 jt 21 jf 17
{.code = OP_JEQ, .jt = 3, .jf = 0, .k = 0x00000044}, // (017) jeq #0x44 jt 21 jf 18
{.code = OP_LDHI, .jt = 0, .jf = 0, .k = 0x00000010}, // (018) ldh [x + 16]
{.code = OP_JEQ, .jt = 1, .jf = 0, .k = 0x00000043}, // (019) jeq #0x43 jt 21 jf 20
{.code = OP_JEQ, .jt = 0, .jf = 1, .k = 0x00000044}, // (020) jeq #0x44 jt 21 jf 22
{.code = OP_RET, .jt = 0, .jf = 0, .k = 0x00040000}, // (021) ret #262144
{.code = OP_RET, .jt = 0, .jf = 0, .k = 0x00000000}, // (022) ret #0
{.code = OP_LDHA, .jt = 0, .jf = 0, .k = 0xfffff004}, // (000) ldh #fffff004
{.code = OP_JEQ, .jt = 22, .jf = 0, .k = 0x00000004}, // (001) jeq #0x04 jt 22 jf 0
{.code = OP_LDHA, .jt = 0, .jf = 0, .k = 0x0000000c}, // (002) ldh [12]
{.code = OP_JEQ, .jt = 0, .jf = 7, .k = 0x000086dd}, // (003) jeq #0x86dd jt 2 jf 9
{.code = OP_LDB, .jt = 0, .jf = 0, .k = 0x00000014}, // (004) ldb [20]
{.code = OP_JEQ, .jt = 0, .jf = 18, .k = 0x00000011}, // (005) jeq #0x11 jt 4 jf 22
{.code = OP_LDHA, .jt = 0, .jf = 0, .k = 0x00000036}, // (006) ldh [54]
{.code = OP_JEQ, .jt = 15, .jf = 0, .k = 0x00000043}, // (007) jeq #0x43 jt 21 jf 6
{.code = OP_JEQ, .jt = 14, .jf = 0, .k = 0x00000044}, // (008) jeq #0x44 jt 21 jf 7
{.code = OP_LDHA, .jt = 0, .jf = 0, .k = 0x00000038}, // (009) ldh [56]
{.code = OP_JEQ, .jt = 12, .jf = 11, .k = 0x00000043}, // (010) jeq #0x43 jt 21 jf 20
{.code = OP_JEQ, .jt = 0, .jf = 12, .k = 0x00000800}, // (011) jeq #0x800 jt 10 jf 22
{.code = OP_LDB, .jt = 0, .jf = 0, .k = 0x00000017}, // (012) ldb [23]
{.code = OP_JEQ, .jt = 0, .jf = 10, .k = 0x00000011}, // (013) jeq #0x11 jt 12 jf 22
{.code = OP_LDHA, .jt = 0, .jf = 0, .k = 0x00000014}, // (014) ldh [20]
{.code = OP_JSET, .jt = 8, .jf = 0, .k = 0x00001fff}, // (015) jset #0x1fff jt 22 jf 14
{.code = OP_LDXB, .jt = 0, .jf = 0, .k = 0x0000000e}, // (016) ldxb 4*([14]&0xf)
{.code = OP_LDHI, .jt = 0, .jf = 0, .k = 0x0000000e}, // (017) ldh [x + 14]
{.code = OP_JEQ, .jt = 4, .jf = 0, .k = 0x00000043}, // (018) jeq #0x43 jt 21 jf 17
{.code = OP_JEQ, .jt = 3, .jf = 0, .k = 0x00000044}, // (019) jeq #0x44 jt 21 jf 18
{.code = OP_LDHI, .jt = 0, .jf = 0, .k = 0x00000010}, // (020) ldh [x + 16]
{.code = OP_JEQ, .jt = 1, .jf = 0, .k = 0x00000043}, // (021) jeq #0x43 jt 21 jf 20
{.code = OP_JEQ, .jt = 0, .jf = 1, .k = 0x00000044}, // (022) jeq #0x44 jt 21 jf 22
{.code = OP_RET, .jt = 0, .jf = 0, .k = 0x00040000}, // (023) ret #262144
{.code = OP_RET, .jt = 0, .jf = 0, .k = 0x00000000}, // (024) ret #0
};
/** Filter program socket struct */
@ -176,7 +186,7 @@ static void read_callback(int fd, short event, void *arg)
uint8_t *dhcphdr = context->buffer + DHCP_START_OFFSET;
int dhcp_option_offset = DHCP_START_OFFSET + DHCP_OPTIONS_HEADER_SIZE;
if ((buffer_sz > UDP_START_OFFSET + sizeof(struct udphdr) + DHCP_OPTIONS_HEADER_SIZE) &&
if (((unsigned)buffer_sz > UDP_START_OFFSET + sizeof(struct udphdr) + DHCP_OPTIONS_HEADER_SIZE) &&
(ntohs(udp->len) > DHCP_OPTIONS_HEADER_SIZE)) {
int dhcp_sz = ntohs(udp->len) < buffer_sz - UDP_START_OFFSET - sizeof(struct udphdr) ?
ntohs(udp->len) : buffer_sz - UDP_START_OFFSET - sizeof(struct udphdr);
@ -221,6 +231,87 @@ static void read_callback(int fd, short event, void *arg)
}
}
/**
* @code read_callback_dual_tor(fd, event, arg);
*
* @brief callback for libevent which is called every time out in order to read queued packet capture when dual tor mode is enabled
*
* @param fd socket to read from
* @param event libevent triggered event
* @param arg user provided argument for callback (interface context)
*
* @return none
*/
static void read_callback_dual_tor(int fd, short event, void *arg)
{
dhcp_device_context_t *context = (dhcp_device_context_t*) arg;
ssize_t buffer_sz;
struct sockaddr_ll sll;
socklen_t slen = sizeof sll;
while ((event == EV_READ) &&
((buffer_sz = recvfrom(fd, context->buffer, context->snaplen, MSG_DONTWAIT, (struct sockaddr *)&sll, &slen)) > 0))
{
std::string member_table = std::string("VLAN_MEMBER|") + context->intf + "|";
char interfaceName[IF_NAMESIZE];
char *interface = if_indextoname(sll.sll_ifindex, interfaceName);
std::string state;
std::string intf(interface);
mStateDbMuxTablePtr->hget(intf, "state", state);
if (state != "standby" && configDb.exists(member_table.append(interface))) {
struct ether_header *ethhdr = (struct ether_header*) context->buffer;
struct ip *iphdr = (struct ip*) (context->buffer + IP_START_OFFSET);
struct udphdr *udp = (struct udphdr*) (context->buffer + UDP_START_OFFSET);
uint8_t *dhcphdr = context->buffer + DHCP_START_OFFSET;
int dhcp_option_offset = DHCP_START_OFFSET + DHCP_OPTIONS_HEADER_SIZE;
if (((unsigned)buffer_sz > UDP_START_OFFSET + sizeof(struct udphdr) + DHCP_OPTIONS_HEADER_SIZE) &&
(ntohs(udp->len) > DHCP_OPTIONS_HEADER_SIZE))
{
int dhcp_sz = ntohs(udp->len) < buffer_sz - UDP_START_OFFSET - sizeof(struct udphdr) ?
ntohs(udp->len) : buffer_sz - UDP_START_OFFSET - sizeof(struct udphdr);
int dhcp_option_sz = dhcp_sz - DHCP_OPTIONS_HEADER_SIZE;
const u_char *dhcp_option = context->buffer + dhcp_option_offset;
dhcp_packet_direction_t dir = (ethhdr->ether_shost[0] == context->mac[0] &&
ethhdr->ether_shost[1] == context->mac[1] &&
ethhdr->ether_shost[2] == context->mac[2] &&
ethhdr->ether_shost[3] == context->mac[3] &&
ethhdr->ether_shost[4] == context->mac[4] &&
ethhdr->ether_shost[5] == context->mac[5]) ?
DHCP_TX : DHCP_RX;
int offset = 0;
int stop_dhcp_processing = 0;
while ((offset < (dhcp_option_sz + 1)) && dhcp_option[offset] != 255) {
switch (dhcp_option[offset])
{
case 53:
if (offset < (dhcp_option_sz + 2)) {
handle_dhcp_option_53(context, &dhcp_option[offset], dir, iphdr, dhcphdr);
}
stop_dhcp_processing = 1; // break while loop since we are only interested in Option 53
break;
default:
break;
}
if (stop_dhcp_processing == 1) {
break;
}
if (dhcp_option[offset] == 0) { // DHCP Option Padding
offset++;
} else {
offset += dhcp_option[offset + 1] + 2;
}
}
} else {
syslog(LOG_WARNING, "read_callback(%s): read length (%ld) is too small to capture DHCP options",
context->intf, buffer_sz);
}
}
}
}
/**
* @code dhcp_device_is_dhcp_inactive(counters);
*
@ -412,7 +503,7 @@ static int init_socket(dhcp_device_context_t *context, const char *intf)
struct sockaddr_ll addr;
memset(&addr, 0, sizeof(addr));
addr.sll_ifindex = if_nametoindex(intf);
addr.sll_ifindex = 0; // any interface
addr.sll_family = AF_PACKET;
addr.sll_protocol = htons(ETH_P_ALL);
if (bind(context->sock, (struct sockaddr *) &addr, sizeof(addr))) {
@ -553,6 +644,7 @@ int dhcp_device_start_capture(dhcp_device_context_t *context,
in_addr_t giaddr_ip)
{
int rv = -1;
struct event *ev;
do {
if (context == NULL) {
@ -579,7 +671,11 @@ int dhcp_device_start_capture(dhcp_device_context_t *context,
break;
}
struct event *ev = event_new(base, context->sock, EV_READ | EV_PERSIST, read_callback, context);
if (dual_tor_sock)
ev = event_new(base, context->sock, EV_READ | EV_PERSIST, read_callback_dual_tor, context);
else
ev = event_new(base, context->sock, EV_READ | EV_PERSIST, read_callback, context);
if (ev == NULL) {
syslog(LOG_ALERT, "event_new: failed to allocate memory for libevent event '%s'\n", strerror(errno));
break;

1
src/dhcpmon/src/dhcp_device.h
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@ -16,6 +16,7 @@
#include <event2/bufferevent.h>
#include <event2/buffer.h>
extern bool dual_tor_sock;
/**
* DHCP message types

2
src/dhcpmon/src/dhcp_devman.c → src/dhcpmon/src/dhcp_devman.cpp
View File

@ -110,7 +110,7 @@ void dhcp_devman_shutdown()
int dhcp_devman_add_intf(const char *name, char intf_type)
{
int rv = -1;
struct intf *dev = malloc(sizeof(struct intf));
struct intf *dev = (struct intf*) malloc(sizeof(struct intf));
if (dev != NULL) {
dev->name = name;

0
src/dhcpmon/src/dhcp_mon.c → src/dhcpmon/src/dhcp_mon.cpp
View File

6
src/dhcpmon/src/main.c → src/dhcpmon/src/main.cpp
View File

@ -16,9 +16,12 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include "subscriberstatetable.h"
#include "select.h"
#include "dhcp_mon.h"
#include "dhcp_devman.h"
#include "dhcp_device.h"
/** dhcpmon_default_snaplen: default snap length of packet being captured */
static const size_t dhcpmon_default_snaplen = 65535;
@ -29,6 +32,8 @@ static const uint32_t dhcpmon_default_health_check_window = 18;
* with DHCP relay */
static const uint32_t dhcpmon_default_unhealthy_max_count = 10;
bool dual_tor_sock = false;
/**
* @code usage(prog);
*
@ -134,6 +139,7 @@ int main(int argc, char **argv)
i += 2;
break;
case 'u':
dual_tor_sock = true;
if (dhcp_devman_setup_dual_tor_mode(argv[i + 1]) != 0) {
usage(basename(argv[0]));
}

14
src/dhcpmon/src/subdir.mk
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@ -1,11 +1,11 @@
# Add inputs and outputs from these tool invocations to the build variables
CC := gcc
CC := g++
C_SRCS += \
../src/dhcp_device.c \
../src/dhcp_devman.c \
../src/dhcp_mon.c \
../src/main.c
../src/dhcp_device.cpp \
../src/dhcp_devman.cpp \
../src/dhcp_mon.cpp \
../src/main.cpp
OBJS += \
./src/dhcp_device.o \
@ -21,9 +21,9 @@ C_DEPS += \
# Each subdirectory must supply rules for building sources it contributes
src/%.o: ../src/%.c
src/%.o: src/%.cpp
@echo 'Building file: $<'
@echo 'Invoking: GCC C Compiler'
$(CC) -O3 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"$(@:%.o=%.d)" -MT"$(@)" -o "$@" "$<"
$(CC) -O3 -g3 -Wall -I$(PWD)/../sonic-swss-common/common -c -fmessage-length=0 -MMD -MP -MF"$(@:%.o=%.d)" -MT"$(@)" -o "$@" "$<"
@echo 'Finished building: $<'
@echo ' '