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Feature/bacnet ipv4 default iface linux (#75)

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* Added default IFACE for IPv4 on Linux

* fix potential leak of memory found by scan-build

Co-authored-by: Steve Karg <skarg@users.sourceforge.net>
This commit is contained in:
Steve Karg
2020-04-16 15:55:38 -05:00
committed by GitHub
parent 8f13d59629
commit dbbcec3033
1 changed files with 232 additions and 17 deletions
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ports/linux/bip-init.c
+232 -17
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@@ -31,9 +31,25 @@
License.
-------------------------------------------
####COPYRIGHTEND####*/
/* linux Ethernet/IP specific */
#include <asm/types.h>
#include <netinet/ether.h>
#include <netinet/in.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <sys/types.h>
#include <unistd.h>
/* standard C */
#include <stdint.h> /* for standard integer types uint8_t etc. */
#include <stdbool.h> /* for the standard bool type. */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
/* BACnet specific */
#include "bacnet/bacdcode.h"
#include "bacnet/bacint.h"
#include "bacnet/datalink/bip.h"
@@ -64,8 +80,10 @@ static bool BIP_Debug = false;
* @param str - debug info string
* @param addr - IPv4 address
*/
static void debug_print_ipv4(const char *str, const struct in_addr *addr,
const unsigned int port, const unsigned int count)
static void debug_print_ipv4(const char *str,
const struct in_addr *addr,
const unsigned int port,
const unsigned int count)
{
if (BIP_Debug) {
fprintf(stderr, "BIP: %s %s:%hu (%u bytes)\n", str, inet_ntoa(*addr),
@@ -229,7 +247,7 @@ uint8_t bip_get_subnet_prefix(void)
if (test_broadcast == broadcast) {
break;
}
mask = mask<<1;
mask = mask << 1;
}
return prefix;
@@ -263,8 +281,8 @@ int bip_send_mpdu(BACNET_IP_ADDRESS *dest, uint8_t *mtu, uint16_t mtu_len)
memcpy(&bip_dest.sin_addr.s_addr, &dest->address[0], 4);
bip_dest.sin_port = htons(dest->port);
/* Send the packet */
debug_print_ipv4("Sending MPDU->", &bip_dest.sin_addr, bip_dest.sin_port,
mtu_len);
debug_print_ipv4(
"Sending MPDU->", &bip_dest.sin_addr, bip_dest.sin_port, mtu_len);
return sendto(BIP_Socket, (char *)mtu, mtu_len, 0,
(struct sockaddr *)&bip_dest, sizeof(struct sockaddr));
}
@@ -337,14 +355,14 @@ uint16_t bip_receive(
*/
memcpy(&addr.address[0], &sin.sin_addr.s_addr, 4);
addr.port = ntohs(sin.sin_port);
debug_print_ipv4("Received MPDU->", &sin.sin_addr, sin.sin_port,
received_bytes);
debug_print_ipv4(
"Received MPDU->", &sin.sin_addr, sin.sin_port, received_bytes);
/* pass the packet into the BBMD handler */
offset = bvlc_handler(&addr, src, npdu, received_bytes);
if (offset > 0) {
npdu_len = received_bytes - offset;
debug_print_ipv4("Received NPDU->", &sin.sin_addr, sin.sin_port,
npdu_len);
debug_print_ipv4(
"Received NPDU->", &sin.sin_addr, sin.sin_port, npdu_len);
if (npdu_len <= max_npdu) {
/* shift the buffer to return a valid NPDU */
for (i = 0; i < npdu_len; i++) {
@@ -445,7 +463,7 @@ static int get_local_ifr_ioctl(char *ifname, struct ifreq *ifr, int request)
*/
int bip_get_local_address_ioctl(char *ifname, struct in_addr *addr, int request)
{
struct ifreq ifr = { {{0}}, {{0}} };
struct ifreq ifr = { { { 0 } }, { { 0 } } };
struct sockaddr_in *tcpip_address;
int rv; /* return value */
@@ -458,6 +476,202 @@ int bip_get_local_address_ioctl(char *ifname, struct in_addr *addr, int request)
return rv;
}
/* structure to hold IPv4 route info when dynamically finding interface */
struct route_info {
uint32_t dstAddr;
uint32_t srcAddr;
uint32_t gateWay;
char ifName[IF_NAMESIZE];
};
/**
* @brief Read the Network Layer socket info
* @param sockFd - socket file descriptor
* @param bufPtr - buffer to hold response from kernel
* @param buf_size - size of the buffer
* @param seqNum - sequence number that tracks our specific request response
* @param pId - process identifier of our specific request response
* @return number of bytes placed into the buffer
*/
static int readNlSock(
int sockFd, char *bufPtr, size_t buf_size, int seqNum, int pId)
{
struct nlmsghdr *nlHdr;
int readLen = 0, msgLen = 0;
do {
/* Receive response from the kernel */
if ((readLen = recv(sockFd, bufPtr, buf_size - msgLen, 0)) < 0) {
perror("SOCK READ: ");
return -1;
}
nlHdr = (struct nlmsghdr *)bufPtr;
/* Check if the header is valid */
if ((0 == NLMSG_OK(nlHdr, readLen)) ||
(NLMSG_ERROR == nlHdr->nlmsg_type)) {
perror("Error in received packet");
return -1;
}
/* Check if it is the last message */
if (NLMSG_DONE == nlHdr->nlmsg_type) {
break;
}
/* Else move the pointer to buffer appropriately */
bufPtr += readLen;
msgLen += readLen;
/* Check if its a multi part message; return if it is not. */
if (0 == (nlHdr->nlmsg_flags & NLM_F_MULTI)) {
break;
}
} while ((nlHdr->nlmsg_seq != seqNum) || (nlHdr->nlmsg_pid != pId));
return msgLen;
}
/**
* @brief Convert an IPv4 address into ASCII dotted decimal
* @param addr - Route info
* @return character string of ASCII dotted decimal
*/
static char *ntoa(uint32_t addr)
{
static char buffer[18];
sprintf(buffer, "%d.%d.%d.%d", (addr & 0x000000FF),
(addr & 0x0000FF00) >> 8, (addr & 0x00FF0000) >> 16,
(addr & 0xFF000000) >> 24);
return buffer;
}
/**
* @brief Printing one route
* @param rtInfo - Route info
*/
static void printRoute(struct route_info *rtInfo)
{
if (BIP_Debug) {
/* Print Destination address */
fprintf(stderr, "%s\t",
rtInfo->dstAddr ? ntoa(rtInfo->dstAddr) : "0.0.0.0 ");
/* Print Gateway address */
fprintf(stderr, "%s\t",
rtInfo->gateWay ? ntoa(rtInfo->gateWay) : "*.*.*.*");
/* Print Interface Name */
fprintf(stderr, "%s\t", rtInfo->ifName);
/* Print Source address */
fprintf(stderr, "%s\n",
rtInfo->srcAddr ? ntoa(rtInfo->srcAddr) : "*.*.*.*");
}
}
/**
* @brief Parse the route info returned from kernel
* @param nlHdr - Network Layer message header from the kernel
* @param rtInfo - Route info
*/
static void parseRoutes(struct nlmsghdr *nlHdr, struct route_info *rtInfo)
{
struct rtmsg *rtMsg;
struct rtattr *rtAttr;
int rtLen;
rtMsg = (struct rtmsg *)NLMSG_DATA(nlHdr);
/* If the route is not for AF_INET or does not belong to main routing table
then return. */
if ((rtMsg->rtm_family != AF_INET) || (rtMsg->rtm_table != RT_TABLE_MAIN))
return;
/* get the rtattr field */
rtAttr = (struct rtattr *)RTM_RTA(rtMsg);
rtLen = RTM_PAYLOAD(nlHdr);
for (; RTA_OK(rtAttr, rtLen); rtAttr = RTA_NEXT(rtAttr, rtLen)) {
switch (rtAttr->rta_type) {
case RTA_OIF:
if_indextoname(*(int *)RTA_DATA(rtAttr), rtInfo->ifName);
break;
case RTA_GATEWAY:
rtInfo->gateWay = *(u_int *)RTA_DATA(rtAttr);
break;
case RTA_PREFSRC:
rtInfo->srcAddr = *(u_int *)RTA_DATA(rtAttr);
break;
case RTA_DST:
rtInfo->dstAddr = *(u_int *)RTA_DATA(rtAttr);
break;
}
}
}
/**
* @brief Get the default interface name using routing info
* @return interface name, or NULL if not found or none
*/
static char *ifname_default(void)
{
static char ifName[IF_NAMESIZE] = { 0 };
struct nlmsghdr *nlMsg = NULL;
struct route_info *rtInfo = NULL;
char msgBuf[8192] = { 0 };
int sock, len, msgSeq = 0;
if (ifName[0] != 0) {
return ifName;
}
/* Create Socket */
if ((sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0) {
perror("Socket Creation: ");
}
/* point the header and the msg structure pointers into the buffer */
nlMsg = (struct nlmsghdr *)msgBuf;
/* Fill in the nlmsg header*/
nlMsg->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
/* Get the routes from kernel routing table */
nlMsg->nlmsg_type = RTM_GETROUTE;
/* The message is a request for dump */
nlMsg->nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST;
/* Sequence of the message packet */
nlMsg->nlmsg_seq = msgSeq++;
/* PID of process sending the request */
nlMsg->nlmsg_pid = getpid();
/* Send the request */
if (send(sock, nlMsg, nlMsg->nlmsg_len, 0) < 0) {
fprintf(stderr, "BIP: Write To Socket Failed...\n");
return ifName;
}
/* Read the response */
if ((len = readNlSock(sock, msgBuf, sizeof(msgBuf), msgSeq, getpid())) <
0) {
fprintf(stderr, "BIP: Read From Socket Failed...\n");
return ifName;
}
/* Parse and print the response */
rtInfo = (struct route_info *)malloc(sizeof(struct route_info));
if (BIP_Debug) {
fprintf(stderr, "Destination\tGateway\tInterface\tSource\n");
}
for (; NLMSG_OK(nlMsg, len); nlMsg = NLMSG_NEXT(nlMsg, len)) {
memset(rtInfo, 0, sizeof(struct route_info));
parseRoutes(nlMsg, rtInfo);
printRoute(rtInfo);
if (ifName[0] == 0) {
if ((rtInfo->dstAddr == 0) && (rtInfo->ifName[0] != 0)) {
/* default route */
memcpy(ifName, rtInfo->ifName, sizeof(ifName));
}
}
}
free(rtInfo);
close(sock);
return ifName;
}
/**
* @brief Get the netmask of the BACnet/IP's interface via an ioctl() call.
* @param netmask [out] The netmask, in host order.
@@ -466,11 +680,13 @@ int bip_get_local_address_ioctl(char *ifname, struct in_addr *addr, int request)
int bip_get_local_netmask(struct in_addr *netmask)
{
int rv;
char *ifname = getenv("BACNET_IFACE"); /* will probably be null */
char *ifname = getenv("BACNET_IFACE");
if (ifname == NULL) {
ifname = "eth0";
ifname = ifname_default();
}
rv = bip_get_local_address_ioctl(ifname, netmask, SIOCGIFNETMASK);
return rv;
}
@@ -527,7 +743,7 @@ void bip_set_interface(char *ifname)
* @note For Linux, ifname is eth0, ath0, arc0, and others.
*
* @param ifname [in] The named interface to use for the network layer.
* If NULL, the "eth0" interface is assigned.
* If NULL, the default interface is assigned.
* @return True if the socket is successfully opened for BACnet/IP,
* else False if the socket functions fail.
*/
@@ -537,16 +753,15 @@ bool bip_init(char *ifname)
struct sockaddr_in sin;
int sockopt = 0;
int sock_fd = -1;
static char *ifname_default = "eth0";
if (ifname) {
bip_set_interface(ifname);
} else {
bip_set_interface(ifname_default);
bip_set_interface(ifname_default());
}
if (BIP_Address.s_addr == 0) {
fprintf(stderr, "BIP: Failed to get an IP address from %s!\n",
ifname?ifname:ifname_default);
ifname ? ifname : ifname_default());
fflush(stderr);
return false;
}