libmac_monitor.c File Reference

Code sample that illustrates the use of the function that receives 802.11 frames in RFMON (monitoring) mode. More...

#include <libmac/libmac.h>

Functions
int	main (int argc, char *argv[])

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Detailed Description

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Function Documentation

int main (  int  argc, char *  argv[] )

Example usage of the 802.11 recv-side function, alongwith the parameter information functions and the interface information functions, follows. This piece of code obtains the list of interfaces using the mac_get_ifinfo function and initializes the parameter structs using the mac_init_params function, requests driver to return parameters using the mac_get_params function, requests driver to set parameters using the mac_set_params function, for the wireless interface passed as a command-line argument, requests driver to append parameters using the mac_append_params function and receives 802.11 frames using the mac_promisc_recv function. frees the parameter and interface information structures using the mac_free_params and the mac_free_ifinfo functions respectively. It returns errno and prints the error information on the screen in case of failure of any of the calls. { // Initializations. int i, j, l, err; struct mac_ifinfo *ifinfo_ptr = NULL; struct mac_ifinfo_list *temp; struct mac_params *params_ptr = NULL; struct mac_params_flags *flags_ptr = NULL; unsigned char *frame_ptr = NULL; unsigned short len = 0; unsigned char *send_parameter_info = NULL, *recv_parameter_info = NULL; unsigned short hdrlen = 0, type_msb, type_lsb; if (argc < 2) { printf("Usage: ./monitor name_of_interface.\n"); return(-1); } // START: ALLOCATE MEMORY FOR THE LIBRARY STRUCTS. ON RECV SIDE. // Get interface information. if ( (err = mac_get_ifinfo(&ifinfo_ptr)) ) { #ifdef DEBUG_ERR printf("Error, error code: %d, %s\n\n", err, strerror(err)); #endif return err; } // Initialize params. struct. and params_flags struct. if ( (err = mac_init_params(&params_ptr, &flags_ptr)) ) { #ifdef DEBUG_ERR printf("Error, error code: %d, %s\n\n", err, strerror(err)); #endif return err; } // END: ALLOCATE MEMORY FOR THE LIBRARY STRUCTS. #ifdef DEBUG_BASIC // Go through the list of interfaces. temp = ifinfo_ptr->mac_list; while (temp != NULL) { // Call the resp. library functions for the interface eth2/wlan0. if ( !(strcmp(temp->if_name, argv[1])) ) { printf("----------- FOR INTERFACE %s -----------\n", temp->if_name); /* Get parameter information from this interface and store it in the mac_params struct. */ if ( (err = mac_get_params(params_ptr, temp, 4, mac_rssi, mac_txpower, mac_noise, mac_currentXmitRate)) ) { #ifdef DEBUG_ERR printf("Error, error code: %d, %s\n\n", err, strerror(err)); #endif return err; } // Print out parameter information retrieved from interface. printf("----------- VALUES AFTER CALL TO GET ------------------\n"); for (i = START_PARAMS_KEY; i < 4; i++) printf("Key: %d, Value: %d\n", params_ptr->key[i], params_ptr->value[i]); // Try to set parameters to the values specified. if ( (err = mac_set_params(params_ptr, temp, 4, mac_noise, 10, mac_rssi, 88, mac_currentXmitRate, 2000000)) ) { #ifdef DEBUG_ERR printf("Error, error code: %d, %s\n\n", err, strerror(err)); #endif return err; } /* Print out the values to which the parameters have been set. If the value printed here corresponds to the largest integer value, it means that the parameter is read-only. If it prints out the largest negative integer value, it means that the parameter is unsupported. */ printf("------------ VALUES AFTER CALL TO SET -----------------\n"); for (i = START_PARAMS_KEY; i < 4; i++) printf("Key: %d, Value: %d\n", params_ptr->key[i], params_ptr->value[i]); /* Call function to append parameter information on all incoming frames. The parameters to be appended in this case are mac_noise and mac_rssi. */ if ( (err = mac_append_params(temp, INCOMING, 2, mac_noise, mac_rssi)) ) { #ifdef DEBUG_ERR printf("Error, error code: %d, %s\n\n", err, strerror(err)); #endif return err; } while(1) { frame_ptr = NULL; len = 0; send_parameter_info = NULL; recv_parameter_info = NULL; hdrlen = 0; type_msb = 4; type_lsb = 4; // Receive 802.11 frames, on specified interface. if ( (err = mac_promisc_recv(&frame_ptr, &len, &send_parameter_info, &recv_parameter_info, temp)) ) { #ifdef DEBUG_ERR printf("Error, error code: %d, %s\n\n", err, strerror(err)); #endif return err; } if (frame_ptr != NULL) { type_msb = frame_ptr[0] & 16; type_lsb = frame_ptr[0] & 32; // MSB is 0 and LSB is 0. if ( (type_msb == 0) && (type_lsb == 0) ) { #ifdef DEBUG_ERR // fprintf(stdout, "Management frame.\n"); #endif hdrlen = 24; } else if ( (type_msb == 0) && (type_lsb == 32) ) { // MSB is 0 and LSB is 1. #ifdef DEBUG_ERR // fprintf(stdout, "Control frame.\n"); #endif hdrlen = 10; } else if ( (type_msb == 16) && (type_lsb == 0) ) { // MSB is 1 and LSB is 0. #ifdef DEBUG_ADV fprintf(stdout, "Data frame.\n"); #endif hdrlen = 24; fprintf(stdout, "=========== 80211 ==============\n"); fprintf(stdout, "Frame control: %hd\n", ((struct ieee_802_11_header *) frame_ptr)->frame_control); fprintf(stdout, "Duration: %hd\n", ((struct ieee_802_11_header *) frame_ptr)->duration); fprintf(stdout, "MAC addr 1: %s\n", pr_ether((unsigned char *) (((struct ieee_802_11_header *) frame_ptr)->mac1))); fprintf(stdout, "MAC addr 2: %s\n", pr_ether((unsigned char *) (((struct ieee_802_11_header *) frame_ptr)->mac2))); fprintf(stdout, "MAC addr 3: %s\n", pr_ether((unsigned char *) (((struct ieee_802_11_header *) frame_ptr)->mac3))); fprintf(stdout, "SeqCtl: %hd\n", ((struct ieee_802_11_header *) frame_ptr)->SeqCtl); fprintf(stdout, "MAC addr 4: %s\n", pr_ether((unsigned char *) (((struct ieee_802_11_header *) frame_ptr)->mac4))); fprintf(stdout, "gapLen: %hd\n", ((struct ieee_802_11_header *) frame_ptr)->gapLen); printf("Length of entire frame: %d\n", len); // Print out length of the received payload in bytes. printf("Length of just payload: %d\n", len - hdrlen); // Check for send-side parameter information. if ( (send_parameter_info) != NULL ) { // Calculate the number of appended parameters. params_ptr->number_of_params = *send_parameter_info; /* Calculate the number of bytes occupied by the appended parameter field. */ l = SIZEOF_PARAMS_LIST_LEN + ( (params_ptr->number_of_params) * (SIZEOF_PARAMS_LIST_KEY + SIZEOF_PARAMS_LIST_VALUE) ); for(j=SIZEOF_PARAMS_LIST_LEN;j < l; j=j+SIZEOF_PARAMS_LIST_VALUE) { printf("Param key: %d\n", send_parameter_info[j]); j = j+SIZEOF_PARAMS_LIST_KEY; printf("Param value: %hd", *((unsigned short *) (send_parameter_info + j))); printf("\n"); } // Check for recv-side parameter information. if ( (recv_parameter_info) != NULL ) { // Calculate the number of appended parameters. params_ptr->number_of_params = *recv_parameter_info; /* Calculate the number of bytes occupied by the appended parameter field. */ l = SIZEOF_PARAMS_LIST_LEN + ( (params_ptr->number_of_params) * (SIZEOF_PARAMS_LIST_KEY + SIZEOF_PARAMS_LIST_VALUE) ); for(j=SIZEOF_PARAMS_LIST_LEN;j < l; j=j+SIZEOF_PARAMS_LIST_VALUE) { printf("Param key: %d\n", recv_parameter_info[j]); j = j+SIZEOF_PARAMS_LIST_KEY; printf("Param value: %hd", *((unsigned short *) (recv_parameter_info + j))); printf("\n"); } } } else { // Check for recv-side parameter information. if ( (recv_parameter_info) != NULL ) { // Calculate the number of appended parameters. params_ptr->number_of_params = *recv_parameter_info; /* Calculate the number of bytes occupied by the appended parameter field. */ l = SIZEOF_PARAMS_LIST_LEN + ( (params_ptr->number_of_params) * (SIZEOF_PARAMS_LIST_KEY + SIZEOF_PARAMS_LIST_VALUE) ); for(j=SIZEOF_PARAMS_LIST_LEN;j < l; j=j+SIZEOF_PARAMS_LIST_VALUE) { printf("Param key: %d\n", recv_parameter_info[j]); j = j+SIZEOF_PARAMS_LIST_KEY; printf("Param value: %hd", *((unsigned short *) (recv_parameter_info + j))); printf("\n"); } } } } else if ( (type_msb == 16) && (type_lsb == 32) ) { // MSB is 1 and LSB is 1. #ifdef DEBUG_ADV fprintf(stdout, "Unrecognized frame type.\n"); #endif hdrlen = 4; } } else fprintf(stdout, "Only ethernet header received.\n"); } } temp = temp->next; } #endif // START: FREE MEMORY ALLOCATED FOR THE LIBRARY STRUCTS. // Free parameter data structures. mac_free_params(&params_ptr, &flags_ptr); // Free interface information collected and return. mac_free_ifinfo(&ifinfo_ptr); // END: FREE MEMORY ALLOCATED FOR THE LIBRARY STRUCTS. return 0; }

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