#include <ctype.h> #include <netlink/attr.h> #include <errno.h> #include <stdbool.h> #include "iw.h" #include "nl80211.h" void mac_addr_n2a(char *mac_addr, unsigned char *arg) { int i, l; l = 0; for (i = 0; i < ETH_ALEN ; i++) { if (i == 0) { sprintf(mac_addr+l, "%02x", arg[i]); l += 2; } else { sprintf(mac_addr+l, ":%02x", arg[i]); l += 3; } } } int mac_addr_a2n(unsigned char *mac_addr, char *arg) { int i; for (i = 0; i < ETH_ALEN ; i++) { int temp; char *cp = strchr(arg, ':'); if (cp) { *cp = 0; cp++; } if (sscanf(arg, "%x", &temp) != 1) return -1; if (temp < 0 || temp > 255) return -1; mac_addr[i] = temp; if (!cp) break; arg = cp; } if (i < ETH_ALEN - 1) return -1; return 0; } int parse_hex_mask(char *hexmask, unsigned char **result, size_t *result_len, unsigned char **mask) { size_t len = strlen(hexmask) / 2; unsigned char *result_val; unsigned char *result_mask = NULL; int pos = 0; *result_len = 0; result_val = calloc(len + 2, 1); if (!result_val) goto error; *result = result_val; if (mask) { result_mask = calloc(DIV_ROUND_UP(len, 8) + 2, 1); if (!result_mask) goto error; *mask = result_mask; } while (1) { char *cp = strchr(hexmask, ':'); if (cp) { *cp = 0; cp++; } if (result_mask && (strcmp(hexmask, "-") == 0 || strcmp(hexmask, "xx") == 0 || strcmp(hexmask, "--") == 0)) { /* skip this byte and leave mask bit unset */ } else { int temp, mask_pos; char *end; temp = strtoul(hexmask, &end, 16); if (*end) goto error; if (temp < 0 || temp > 255) goto error; result_val[pos] = temp; mask_pos = pos / 8; if (result_mask) result_mask[mask_pos] |= 1 << (pos % 8); } (*result_len)++; pos++; if (!cp) break; hexmask = cp; } return 0; error: free(result_val); free(result_mask); return -1; } unsigned char *parse_hex(char *hex, size_t *outlen) { unsigned char *result; if (parse_hex_mask(hex, &result, outlen, NULL)) return NULL; return result; } static const char *ifmodes[NL80211_IFTYPE_MAX + 1] = { "unspecified", "IBSS", "managed", "AP", "AP/VLAN", "WDS", "monitor", "mesh point", "P2P-client", "P2P-GO", "P2P-device", "outside context of a BSS", }; static char modebuf[100]; const char *iftype_name(enum nl80211_iftype iftype) { if (iftype <= NL80211_IFTYPE_MAX && ifmodes[iftype]) return ifmodes[iftype]; sprintf(modebuf, "Unknown mode (%d)", iftype); return modebuf; } static const char *commands[NL80211_CMD_MAX + 1] = { /* * sed 's/^\tNL80211_CMD_//;t n;d;:n s%^\([^=]*\),.*%\t[NL80211_CMD_\1] = \"\L\1\",%;t;d' nl80211.h */ [NL80211_CMD_UNSPEC] = "unspec", [NL80211_CMD_GET_WIPHY] = "get_wiphy", [NL80211_CMD_SET_WIPHY] = "set_wiphy", [NL80211_CMD_NEW_WIPHY] = "new_wiphy", [NL80211_CMD_DEL_WIPHY] = "del_wiphy", [NL80211_CMD_GET_INTERFACE] = "get_interface", [NL80211_CMD_SET_INTERFACE] = "set_interface", [NL80211_CMD_NEW_INTERFACE] = "new_interface", [NL80211_CMD_DEL_INTERFACE] = "del_interface", [NL80211_CMD_GET_KEY] = "get_key", [NL80211_CMD_SET_KEY] = "set_key", [NL80211_CMD_NEW_KEY] = "new_key", [NL80211_CMD_DEL_KEY] = "del_key", [NL80211_CMD_GET_BEACON] = "get_beacon", [NL80211_CMD_SET_BEACON] = "set_beacon", [NL80211_CMD_START_AP] = "start_ap", [NL80211_CMD_STOP_AP] = "stop_ap", [NL80211_CMD_GET_STATION] = "get_station", [NL80211_CMD_SET_STATION] = "set_station", [NL80211_CMD_NEW_STATION] = "new_station", [NL80211_CMD_DEL_STATION] = "del_station", [NL80211_CMD_GET_MPATH] = "get_mpath", [NL80211_CMD_SET_MPATH] = "set_mpath", [NL80211_CMD_NEW_MPATH] = "new_mpath", [NL80211_CMD_DEL_MPATH] = "del_mpath", [NL80211_CMD_SET_BSS] = "set_bss", [NL80211_CMD_SET_REG] = "set_reg", [NL80211_CMD_REQ_SET_REG] = "req_set_reg", [NL80211_CMD_GET_MESH_CONFIG] = "get_mesh_config", [NL80211_CMD_SET_MESH_CONFIG] = "set_mesh_config", [NL80211_CMD_GET_REG] = "get_reg", [NL80211_CMD_GET_SCAN] = "get_scan", [NL80211_CMD_TRIGGER_SCAN] = "trigger_scan", [NL80211_CMD_NEW_SCAN_RESULTS] = "new_scan_results", [NL80211_CMD_SCAN_ABORTED] = "scan_aborted", [NL80211_CMD_REG_CHANGE] = "reg_change", [NL80211_CMD_AUTHENTICATE] = "authenticate", [NL80211_CMD_ASSOCIATE] = "associate", [NL80211_CMD_DEAUTHENTICATE] = "deauthenticate", [NL80211_CMD_DISASSOCIATE] = "disassociate", [NL80211_CMD_MICHAEL_MIC_FAILURE] = "michael_mic_failure", [NL80211_CMD_REG_BEACON_HINT] = "reg_beacon_hint", [NL80211_CMD_JOIN_IBSS] = "join_ibss", [NL80211_CMD_LEAVE_IBSS] = "leave_ibss", [NL80211_CMD_TESTMODE] = "testmode", [NL80211_CMD_CONNECT] = "connect", [NL80211_CMD_ROAM] = "roam", [NL80211_CMD_DISCONNECT] = "disconnect", [NL80211_CMD_SET_WIPHY_NETNS] = "set_wiphy_netns", [NL80211_CMD_GET_SURVEY] = "get_survey", [NL80211_CMD_NEW_SURVEY_RESULTS] = "new_survey_results", [NL80211_CMD_SET_PMKSA] = "set_pmksa", [NL80211_CMD_DEL_PMKSA] = "del_pmksa", [NL80211_CMD_FLUSH_PMKSA] = "flush_pmksa", [NL80211_CMD_REMAIN_ON_CHANNEL] = "remain_on_channel", [NL80211_CMD_CANCEL_REMAIN_ON_CHANNEL] = "cancel_remain_on_channel", [NL80211_CMD_SET_TX_BITRATE_MASK] = "set_tx_bitrate_mask", [NL80211_CMD_REGISTER_FRAME] = "register_frame", [NL80211_CMD_FRAME] = "frame", [NL80211_CMD_FRAME_TX_STATUS] = "frame_tx_status", [NL80211_CMD_SET_POWER_SAVE] = "set_power_save", [NL80211_CMD_GET_POWER_SAVE] = "get_power_save", [NL80211_CMD_SET_CQM] = "set_cqm", [NL80211_CMD_NOTIFY_CQM] = "notify_cqm", [NL80211_CMD_SET_CHANNEL] = "set_channel", [NL80211_CMD_SET_WDS_PEER] = "set_wds_peer", [NL80211_CMD_FRAME_WAIT_CANCEL] = "frame_wait_cancel", [NL80211_CMD_JOIN_MESH] = "join_mesh", [NL80211_CMD_LEAVE_MESH] = "leave_mesh", [NL80211_CMD_UNPROT_DEAUTHENTICATE] = "unprot_deauthenticate", [NL80211_CMD_UNPROT_DISASSOCIATE] = "unprot_disassociate", [NL80211_CMD_NEW_PEER_CANDIDATE] = "new_peer_candidate", [NL80211_CMD_GET_WOWLAN] = "get_wowlan", [NL80211_CMD_SET_WOWLAN] = "set_wowlan", [NL80211_CMD_START_SCHED_SCAN] = "start_sched_scan", [NL80211_CMD_STOP_SCHED_SCAN] = "stop_sched_scan", [NL80211_CMD_SCHED_SCAN_RESULTS] = "sched_scan_results", [NL80211_CMD_SCHED_SCAN_STOPPED] = "sched_scan_stopped", [NL80211_CMD_SET_REKEY_OFFLOAD] = "set_rekey_offload", [NL80211_CMD_PMKSA_CANDIDATE] = "pmksa_candidate", [NL80211_CMD_TDLS_OPER] = "tdls_oper", [NL80211_CMD_TDLS_MGMT] = "tdls_mgmt", [NL80211_CMD_UNEXPECTED_FRAME] = "unexpected_frame", [NL80211_CMD_PROBE_CLIENT] = "probe_client", [NL80211_CMD_REGISTER_BEACONS] = "register_beacons", [NL80211_CMD_UNEXPECTED_4ADDR_FRAME] = "unexpected_4addr_frame", [NL80211_CMD_SET_NOACK_MAP] = "set_noack_map", [NL80211_CMD_CH_SWITCH_NOTIFY] = "ch_switch_notify", [NL80211_CMD_START_P2P_DEVICE] = "start_p2p_device", [NL80211_CMD_STOP_P2P_DEVICE] = "stop_p2p_device", [NL80211_CMD_CONN_FAILED] = "conn_failed", [NL80211_CMD_SET_MCAST_RATE] = "set_mcast_rate", [NL80211_CMD_SET_MAC_ACL] = "set_mac_acl", [NL80211_CMD_RADAR_DETECT] = "radar_detect", [NL80211_CMD_GET_PROTOCOL_FEATURES] = "get_protocol_features", [NL80211_CMD_UPDATE_FT_IES] = "update_ft_ies", [NL80211_CMD_FT_EVENT] = "ft_event", [NL80211_CMD_CRIT_PROTOCOL_START] = "crit_protocol_start", [NL80211_CMD_CRIT_PROTOCOL_STOP] = "crit_protocol_stop", [NL80211_CMD_GET_COALESCE] = "get_coalesce", [NL80211_CMD_SET_COALESCE] = "set_coalesce", [NL80211_CMD_CHANNEL_SWITCH] = "channel_switch", [NL80211_CMD_VENDOR] = "vendor", [NL80211_CMD_SET_QOS_MAP] = "set_qos_map", [NL80211_CMD_ADD_TX_TS] = "add_tx_ts", [NL80211_CMD_DEL_TX_TS] = "del_tx_ts", [NL80211_CMD_GET_MPP] = "get_mpp", [NL80211_CMD_JOIN_OCB] = "join_ocb", [NL80211_CMD_LEAVE_OCB] = "leave_ocb", [NL80211_CMD_CH_SWITCH_STARTED_NOTIFY] = "ch_switch_started_notify", }; static char cmdbuf[100]; const char *command_name(enum nl80211_commands cmd) { if (cmd <= NL80211_CMD_MAX && commands[cmd]) return commands[cmd]; sprintf(cmdbuf, "Unknown command (%d)", cmd); return cmdbuf; } int ieee80211_channel_to_frequency(int chan, enum nl80211_band band) { /* see 802.11 17.3.8.3.2 and Annex J * there are overlapping channel numbers in 5GHz and 2GHz bands */ if (chan <= 0) return 0; /* not supported */ switch (band) { case NL80211_BAND_2GHZ: if (chan == 14) return 2484; else if (chan < 14) return 2407 + chan * 5; break; case NL80211_BAND_5GHZ: if (chan >= 182 && chan <= 196) return 4000 + chan * 5; else return 5000 + chan * 5; break; case NL80211_BAND_60GHZ: if (chan < 5) return 56160 + chan * 2160; break; default: ; } return 0; /* not supported */ } int ieee80211_frequency_to_channel(int freq) { /* see 802.11-2007 17.3.8.3.2 and Annex J */ if (freq == 2484) return 14; else if (freq < 2484) return (freq - 2407) / 5; else if (freq >= 4910 && freq <= 4980) return (freq - 4000) / 5; else if (freq <= 45000) /* DMG band lower limit */ return (freq - 5000) / 5; else if (freq >= 58320 && freq <= 64800) return (freq - 56160) / 2160; else return 0; } void print_ssid_escaped(const uint8_t len, const uint8_t *data) { int i; for (i = 0; i < len; i++) { if (isprint(data[i]) && data[i] != ' ' && data[i] != '\\') printf("%c", data[i]); else if (data[i] == ' ' && (i != 0 && i != len -1)) printf(" "); else printf("\\x%.2x", data[i]); } } static int hex2num(char digit) { if (!isxdigit(digit)) return -1; if (isdigit(digit)) return digit - '0'; return tolower(digit) - 'a' + 10; } static int hex2byte(char *hex) { int d1, d2; d1 = hex2num(hex[0]); if (d1 < 0) return -1; d2 = hex2num(hex[1]); if (d2 < 0) return -1; return (d1 << 4) | d2; } static char *hex2bin(char *hex, char *buf) { char *result = buf; int d; while (hex[0]) { d = hex2byte(hex); if (d < 0) return NULL; buf[0] = d; buf++; hex += 2; } return result; } int parse_keys(struct nl_msg *msg, char **argv, int argc) { struct nlattr *keys; int i = 0; bool have_default = false; char keybuf[13]; if (!argc) return 1; NLA_PUT_FLAG(msg, NL80211_ATTR_PRIVACY); keys = nla_nest_start(msg, NL80211_ATTR_KEYS); if (!keys) return -ENOBUFS; do { char *arg = *argv; int pos = 0, keylen; struct nlattr *key = nla_nest_start(msg, ++i); char *keydata; if (!key) return -ENOBUFS; if (arg[pos] == 'd') { NLA_PUT_FLAG(msg, NL80211_KEY_DEFAULT); pos++; if (arg[pos] == ':') pos++; have_default = true; } if (!isdigit(arg[pos])) goto explain; NLA_PUT_U8(msg, NL80211_KEY_IDX, arg[pos++] - '0'); if (arg[pos++] != ':') goto explain; keydata = arg + pos; switch (strlen(keydata)) { case 10: keydata = hex2bin(keydata, keybuf); case 5: NLA_PUT_U32(msg, NL80211_KEY_CIPHER, 0x000FAC01); keylen = 5; break; case 26: keydata = hex2bin(keydata, keybuf); case 13: NLA_PUT_U32(msg, NL80211_KEY_CIPHER, 0x000FAC05); keylen = 13; break; default: goto explain; } if (!keydata) goto explain; NLA_PUT(msg, NL80211_KEY_DATA, keylen, keydata); argv++; argc--; /* one key should be TX key */ if (!have_default && !argc) NLA_PUT_FLAG(msg, NL80211_KEY_DEFAULT); nla_nest_end(msg, key); } while (argc); nla_nest_end(msg, keys); return 0; nla_put_failure: return -ENOBUFS; explain: fprintf(stderr, "key must be [d:]index:data where\n" " 'd:' means default (transmit) key\n" " 'index:' is a single digit (0-3)\n" " 'data' must be 5 or 13 ascii chars\n" " or 10 or 26 hex digits\n" "for example: d:2:6162636465 is the same as d:2:abcde\n"); return 2; } static void print_mcs_index(const __u8 *mcs) { int mcs_bit, prev_bit = -2, prev_cont = 0; for (mcs_bit = 0; mcs_bit <= 76; mcs_bit++) { unsigned int mcs_octet = mcs_bit/8; unsigned int MCS_RATE_BIT = 1 << mcs_bit % 8; bool mcs_rate_idx_set; mcs_rate_idx_set = !!(mcs[mcs_octet] & MCS_RATE_BIT); if (!mcs_rate_idx_set) continue; if (prev_bit != mcs_bit - 1) { if (prev_bit != -2) printf("%d, ", prev_bit); else printf(" "); printf("%d", mcs_bit); prev_cont = 0; } else if (!prev_cont) { printf("-"); prev_cont = 1; } prev_bit = mcs_bit; } if (prev_cont) printf("%d", prev_bit); printf("\n"); } /* * There are only 4 possible values, we just use a case instead of computing it, * but technically this can also be computed through the formula: * * Max AMPDU length = (2 ^ (13 + exponent)) - 1 bytes */ static __u32 compute_ampdu_length(__u8 exponent) { switch (exponent) { case 0: return 8191; /* (2 ^(13 + 0)) -1 */ case 1: return 16383; /* (2 ^(13 + 1)) -1 */ case 2: return 32767; /* (2 ^(13 + 2)) -1 */ case 3: return 65535; /* (2 ^(13 + 3)) -1 */ default: return 0; } } static const char *print_ampdu_space(__u8 space) { switch (space) { case 0: return "No restriction"; case 1: return "1/4 usec"; case 2: return "1/2 usec"; case 3: return "1 usec"; case 4: return "2 usec"; case 5: return "4 usec"; case 6: return "8 usec"; case 7: return "16 usec"; default: return "BUG (spacing more than 3 bits!)"; } } void print_ampdu_length(__u8 exponent) { __u32 max_ampdu_length; max_ampdu_length = compute_ampdu_length(exponent); if (max_ampdu_length) { printf("\t\tMaximum RX AMPDU length %d bytes (exponent: 0x0%02x)\n", max_ampdu_length, exponent); } else { printf("\t\tMaximum RX AMPDU length: unrecognized bytes " "(exponent: %d)\n", exponent); } } void print_ampdu_spacing(__u8 spacing) { printf("\t\tMinimum RX AMPDU time spacing: %s (0x%02x)\n", print_ampdu_space(spacing), spacing); } void print_ht_capability(__u16 cap) { #define PRINT_HT_CAP(_cond, _str) \ do { \ if (_cond) \ printf("\t\t\t" _str "\n"); \ } while (0) printf("\t\tCapabilities: 0x%02x\n", cap); PRINT_HT_CAP((cap & BIT(0)), "RX LDPC"); PRINT_HT_CAP((cap & BIT(1)), "HT20/HT40"); PRINT_HT_CAP(!(cap & BIT(1)), "HT20"); PRINT_HT_CAP(((cap >> 2) & 0x3) == 0, "Static SM Power Save"); PRINT_HT_CAP(((cap >> 2) & 0x3) == 1, "Dynamic SM Power Save"); PRINT_HT_CAP(((cap >> 2) & 0x3) == 3, "SM Power Save disabled"); PRINT_HT_CAP((cap & BIT(4)), "RX Greenfield"); PRINT_HT_CAP((cap & BIT(5)), "RX HT20 SGI"); PRINT_HT_CAP((cap & BIT(6)), "RX HT40 SGI"); PRINT_HT_CAP((cap & BIT(7)), "TX STBC"); PRINT_HT_CAP(((cap >> 8) & 0x3) == 0, "No RX STBC"); PRINT_HT_CAP(((cap >> 8) & 0x3) == 1, "RX STBC 1-stream"); PRINT_HT_CAP(((cap >> 8) & 0x3) == 2, "RX STBC 2-streams"); PRINT_HT_CAP(((cap >> 8) & 0x3) == 3, "RX STBC 3-streams"); PRINT_HT_CAP((cap & BIT(10)), "HT Delayed Block Ack"); PRINT_HT_CAP(!(cap & BIT(11)), "Max AMSDU length: 3839 bytes"); PRINT_HT_CAP((cap & BIT(11)), "Max AMSDU length: 7935 bytes"); /* * For beacons and probe response this would mean the BSS * does or does not allow the usage of DSSS/CCK HT40. * Otherwise it means the STA does or does not use * DSSS/CCK HT40. */ PRINT_HT_CAP((cap & BIT(12)), "DSSS/CCK HT40"); PRINT_HT_CAP(!(cap & BIT(12)), "No DSSS/CCK HT40"); /* BIT(13) is reserved */ PRINT_HT_CAP((cap & BIT(14)), "40 MHz Intolerant"); PRINT_HT_CAP((cap & BIT(15)), "L-SIG TXOP protection"); #undef PRINT_HT_CAP } void print_ht_mcs(const __u8 *mcs) { /* As defined in 7.3.2.57.4 Supported MCS Set field */ unsigned int tx_max_num_spatial_streams, max_rx_supp_data_rate; bool tx_mcs_set_defined, tx_mcs_set_equal, tx_unequal_modulation; max_rx_supp_data_rate = (mcs[10] | ((mcs[11] & 0x3) << 8)); tx_mcs_set_defined = !!(mcs[12] & (1 << 0)); tx_mcs_set_equal = !(mcs[12] & (1 << 1)); tx_max_num_spatial_streams = ((mcs[12] >> 2) & 3) + 1; tx_unequal_modulation = !!(mcs[12] & (1 << 4)); if (max_rx_supp_data_rate) printf("\t\tHT Max RX data rate: %d Mbps\n", max_rx_supp_data_rate); /* XXX: else see 9.6.0e.5.3 how to get this I think */ if (tx_mcs_set_defined) { if (tx_mcs_set_equal) { printf("\t\tHT TX/RX MCS rate indexes supported:"); print_mcs_index(mcs); } else { printf("\t\tHT RX MCS rate indexes supported:"); print_mcs_index(mcs); if (tx_unequal_modulation) printf("\t\tTX unequal modulation supported\n"); else printf("\t\tTX unequal modulation not supported\n"); printf("\t\tHT TX Max spatial streams: %d\n", tx_max_num_spatial_streams); printf("\t\tHT TX MCS rate indexes supported may differ\n"); } } else { printf("\t\tHT RX MCS rate indexes supported:"); print_mcs_index(mcs); printf("\t\tHT TX MCS rate indexes are undefined\n"); } } void print_vht_info(__u32 capa, const __u8 *mcs) { __u16 tmp; int i; printf("\t\tVHT Capabilities (0x%.8x):\n", capa); #define PRINT_VHT_CAPA(_bit, _str) \ do { \ if (capa & BIT(_bit)) \ printf("\t\t\t" _str "\n"); \ } while (0) printf("\t\t\tMax MPDU length: "); switch (capa & 3) { case 0: printf("3895\n"); break; case 1: printf("7991\n"); break; case 2: printf("11454\n"); break; case 3: printf("(reserved)\n"); } printf("\t\t\tSupported Channel Width: "); switch ((capa >> 2) & 3) { case 0: printf("neither 160 nor 80+80\n"); break; case 1: printf("160 MHz\n"); break; case 2: printf("160 MHz, 80+80 MHz\n"); break; case 3: printf("(reserved)\n"); } PRINT_VHT_CAPA(4, "RX LDPC"); PRINT_VHT_CAPA(5, "short GI (80 MHz)"); PRINT_VHT_CAPA(6, "short GI (160/80+80 MHz)"); PRINT_VHT_CAPA(7, "TX STBC"); /* RX STBC */ PRINT_VHT_CAPA(11, "SU Beamformer"); PRINT_VHT_CAPA(12, "SU Beamformee"); /* compressed steering */ /* # of sounding dimensions */ PRINT_VHT_CAPA(19, "MU Beamformer"); PRINT_VHT_CAPA(20, "MU Beamformee"); PRINT_VHT_CAPA(21, "VHT TXOP PS"); PRINT_VHT_CAPA(22, "+HTC-VHT"); /* max A-MPDU */ /* VHT link adaptation */ PRINT_VHT_CAPA(28, "RX antenna pattern consistency"); PRINT_VHT_CAPA(29, "TX antenna pattern consistency"); printf("\t\tVHT RX MCS set:\n"); tmp = mcs[0] | (mcs[1] << 8); for (i = 1; i <= 8; i++) { printf("\t\t\t%d streams: ", i); switch ((tmp >> ((i-1)*2) ) & 3) { case 0: printf("MCS 0-7\n"); break; case 1: printf("MCS 0-8\n"); break; case 2: printf("MCS 0-9\n"); break; case 3: printf("not supported\n"); break; } } tmp = mcs[2] | (mcs[3] << 8); printf("\t\tVHT RX highest supported: %d Mbps\n", tmp & 0x1fff); printf("\t\tVHT TX MCS set:\n"); tmp = mcs[4] | (mcs[5] << 8); for (i = 1; i <= 8; i++) { printf("\t\t\t%d streams: ", i); switch ((tmp >> ((i-1)*2) ) & 3) { case 0: printf("MCS 0-7\n"); break; case 1: printf("MCS 0-8\n"); break; case 2: printf("MCS 0-9\n"); break; case 3: printf("not supported\n"); break; } } tmp = mcs[6] | (mcs[7] << 8); printf("\t\tVHT TX highest supported: %d Mbps\n", tmp & 0x1fff); } void iw_hexdump(const char *prefix, const __u8 *buf, size_t size) { int i; printf("%s: ", prefix); for (i = 0; i < size; i++) { if (i && i % 16 == 0) printf("\n%s: ", prefix); printf("%02x ", buf[i]); } printf("\n\n"); }