dahdi_tools 分析（一）dahdi_scan
dahdi_tools 分析（一）dahdi_scan
dahdi_scan 的使用
示例：
# dahdi_scan
[1]
active=yes
alarms=OK
description= XX WCTDM Board 1
name=WCTDM/0
manufacturer=xx
devicetype=xx
location=PCI Bus 00 Slot 00
basechan=1
totchans=4
irq=0
type=analog
port=1,FXS
port=2,FXS
port=3,FXS
port=4,FXS
dahdi_scan 用于显示板卡的一些信息。无参数时扫描所有板卡信息，加参数时扫描指定板卡，如 dahdi_scan 4 5 6 ；只扫描 4 5 6 号板卡。
源码分析
int main(int argc, char *argv[])
{
int ctl;
int x, y, z;
struct dahdi_params params;
unsigned int basechan = 1;
int direct_basechan;
struct dahdi_spaninfo s;
char buf[100];
char alarms[50];
// 打开 /dev/dahdi/ctl
if ((ctl = open("/dev/dahdi/ctl", O_RDWR)) < 0) {
fprintf(stderr, "Unable to open /dev/dahdi/ctl: %s\n", strerror(errno));
exit(1);
}
for (x = 1; x < DAHDI_MAX_SPANS; x++) {
memset(&s, 0, sizeof(s));
s.spanno = x;
if (ioctl(ctl, DAHDI_SPANSTAT, &s)) // 使用 ioctl DAHDI_SPANSTAT 获取板卡信息，struct dahdi_spaninfo
continue;
/* DAHDI-Linux 2.5.x exposes the base channel in sysfs. Let's
* try to look for it there in case there are holes in the span
* numbering. */
direct_basechan = get_basechan(x); // get_basechan 后面分析
if (-1 != direct_basechan) {
basechan = direct_basechan;
}
fprintf(stdout, "[%d]\n", x);
fprintf(stdout, "active=yes\n");
fprintf(stdout, "alarms=%s\n", alarms);
fprintf(stdout, "description=%s\n", s.desc);
fprintf(stdout, "name=%s\n", s.name);
fprintf(stdout, "manufacturer=%s\n", s.manufacturer);
fprintf(stdout, "devicetype=%s\n", s.devicetype);
fprintf(stdout, "location=%s\n", s.location);
fprintf(stdout, "basechan=%d\n", basechan);
fprintf(stdout, "totchans=%d\n", s.totalchans);
fprintf(stdout, "irq=%d\n", s.irq); // 显示一些基本信息
y = basechan;
memset(¶ms, 0, sizeof(params));
params.channo = y;
if (ioctl(ctl, DAHDI_GET_PARAMS, ¶ms)) { // 看是否能获取其它信息
basechan += s.totalchans;
continue;
}
if (is_digital_span(&s)) { // 判断是数字板卡还是模拟板卡
/* this is a digital span */
fprintf(stdout, "type=digital-%s\n", s.spantype);
fprintf(stdout, "syncsrc=%d\n", s.syncsrc);
fprintf(stdout, "lbo=%s\n", s.lboname);
fprintf(stdout, "coding_opts=");
buf[0] = '\0';
if (s.linecompat & DAHDI_CONFIG_B8ZS) strcat(buf, "B8ZS,");
if (s.linecompat & DAHDI_CONFIG_AMI) strcat(buf, "AMI,");
if (s.linecompat & DAHDI_CONFIG_HDB3) strcat(buf, "HDB3,");
buf[strlen(buf) - 1] = '\0';
fprintf(stdout, "%s\n", buf);
fprintf(stdout, "framing_opts=");
buf[0] = '\0';
if (s.linecompat & DAHDI_CONFIG_ESF) strcat(buf, "ESF,");
if (s.linecompat & DAHDI_CONFIG_D4) strcat(buf, "D4,");
if (s.linecompat & DAHDI_CONFIG_CCS) strcat(buf, "CCS,");
if (s.linecompat & DAHDI_CONFIG_CRC4) strcat(buf, "CRC4,");
buf[strlen(buf) - 1] = '\0';
fprintf(stdout, "%s\n", buf);
fprintf(stdout, "coding=");
if (s.lineconfig & DAHDI_CONFIG_B8ZS) fprintf(stdout, "B8ZS");
else if (s.lineconfig & DAHDI_CONFIG_AMI) fprintf(stdout, "AMI");
else if (s.lineconfig & DAHDI_CONFIG_HDB3) fprintf(stdout, "HDB3");
fprintf(stdout, "\n");
fprintf(stdout, "framing=");
if (s.lineconfig & DAHDI_CONFIG_ESF) fprintf(stdout, "ESF");
else if (s.lineconfig & DAHDI_CONFIG_D4) fprintf(stdout, "D4");
else if (s.lineconfig & DAHDI_CONFIG_CCS) fprintf(stdout, "CCS");
else fprintf(stdout, "CAS");
if (s.lineconfig & DAHDI_CONFIG_CRC4) fprintf(stdout, "/CRC4");
fprintf(stdout, "\n");
} else {
/* this is an analog span */
fprintf(stdout, "type=analog\n");
for (y = basechan; y < (basechan + s.totalchans); y++) {
memset(¶ms, 0, sizeof(params));
params.channo = y;
if (ioctl(ctl, DAHDI_GET_PARAMS, ¶ms)) { // 获取params参数
fprintf(stdout, "port=%d,unknown\n", y);
continue;
};
fprintf(stdout, "port=%d,", y);
switch (params.sigcap & (__DAHDI_SIG_FXO | __DAHDI_SIG_FXS)) { // 根据 params.sigcap 区分是FXS还是FXO
case __DAHDI_SIG_FXO:
fprintf(stdout, "FXS");
break;
case __DAHDI_SIG_FXS:
fprintf(stdout, "FXO");
break;
default:
fprintf(stdout, "none");
}
if (params.sigcap & DAHDI_SIG_BROKEN)
fprintf(stdout, " FAILED");
fprintf(stdout, "\n");
}
}
basechan += s.totalchans;
}
}
代码里面核心的部分就是 ioctl DAHDI_SPANSTAT 获取板卡信息，即 struct dahdi_spaninfo ，然后打印出来。然后根据是数字板卡还是模拟板卡打印不同的信息。
有两个函数这里分析一下
- get_basechan
- is_digital_span
get_basechan
static int get_basechan(unsigned int spanno)
{
int res;
int basechan;
char filename[256];
FILE *fp;
snprintf(filename, sizeof(filename),
"/sys/bus/dahdi_spans/devices/span-%u/basechan", spanno);
fp = fopen(filename, "r");
if (NULL == fp) {
return -1;
}
res = fscanf(fp, "%d", &basechan);
fclose(fp);
if (EOF == res) {
return -1;
}
return basechan;
}
通过读取 /sys/bus/dahdi_spans/devices/span-x/basechan , 来获取 basechan ，即该板卡 的第一个通道的号码。
当一个系统上存在多个板卡时。ls /sys/bus/dahdi_spans/devices 可以看的到
# ls /sys/bus/dahdi_spans/devices
span-1 span-2 span-3 span-4 span-5 span-6 span-7 span-8 span-9
进去可以看到：
span-1]# ls -1
alarms
basechan
channels
dahdi!chan!001!001
...
...
ddev
desc
driver
is_digital
is_sync_master
lbo
linecompat
lineconfig
local_spanno
name
power
spantype
subsystem
syncsrc
uevent
is_digital_span
static inline int is_digital_span(struct dahdi_spaninfo *s)
{
return (s->linecompat > 0);
}
s->linecompat > 0 时表示数字板卡。
struct dahdi_spaninfo
数据结构定义如下：
struct dahdi_spaninfo {
int spanno; /* span number */
char name[20]; /* Name */
char desc[40]; /* Description */
int alarms; /* alarms status */
int txlevel; /* what TX level is set to */
int rxlevel; /* current RX level */
int bpvcount; /* current BPV count */
int crc4count; /* current CRC4 error count */
int ebitcount; /* current E-bit error count */
int fascount; /* current FAS error count */
__u32 fecount; /* Framing error counter */
__u32 cvcount; /* Coding violations counter */
__u32 becount; /* current bit error count */
__u32 prbs; /* current PRBS detected pattern */
__u32 errsec; /* errored seconds */
int irqmisses; /* current IRQ misses */
int syncsrc; /* span # of current sync source,
or 0 for free run */
int numchans; /* number of configured channels on this span */
int totalchans; /* total number of channels on the span */
int totalspans; /* total number of spans in entire system */
int lbo; /* line build out */
int lineconfig; /* framing/coding */
char lboname[40]; /* line build out in text form */
char location[40]; /* span's device location in system */
char manufacturer[40]; /* manufacturer of span's device */
char devicetype[40]; /* span's device type */
int irq; /* span's device IRQ */
int linecompat; /* span global signaling or 0 for
analog spans.*/
char spantype[6]; /* type of span in text form */
}