gping.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

#include <u.h>
#include <libc.h>
#include <ctype.h>
#include <auth.h>
#include <fcall.h>
#include <draw.h>
#include <event.h>
#include <ip.h>

#define	MAXNUM	8	/* maximum number of numbers on data line */

typedef struct Graph	Graph;
typedef struct Machine	Machine;
typedef struct Req	Req;
typedef struct Icmp	Icmp;

enum {
	Gmsglen	= 16,
};

struct Graph
{
	int		colindex;
	Rectangle	r;
	int		*data;
	int		ndata;
	char		*label;
	void		(*newvalue)(Machine*, long*, long*, long*);
	void		(*update)(Graph*, long, long, long);
	Machine		*mach;
	int		overflow;
	Image		*overtmp;
	int		overtmplen;
	char		msg[Gmsglen];
	int		cursor;
	int		vmax;
};

struct Icmp
{
	uchar	vihl;		/* Version and header length */
	uchar	tos;		/* Type of service */
	uchar	length[2];	/* packet length */
	uchar	id[2];		/* Identification */
	uchar	frag[2];	/* Fragment information */
	uchar	ttl;		/* Time to live */
	uchar	proto;		/* Protocol */
	uchar	ipcksum[2];	/* Header checksum */
	uchar	src[4];		/* Ip source */
	uchar	dst[4];		/* Ip destination */
	uchar	type;
	uchar	code;
	uchar	cksum[2];
	uchar	icmpid[2];
	uchar	seq[2];
	uchar	data[1];
};

enum
{			/* Packet Types */
	EchoReply	= 0,
	Unreachable	= 3,
	SrcQuench	= 4,
	EchoRequest	= 8,
	TimeExceed	= 11,
	Timestamp	= 13,
	TimestampReply	= 14,
	InfoRequest	= 15,
	InfoReply	= 16,

	ICMP_IPSIZE	= 20,
	ICMP_HDRSIZE	= 8,

	MSGLEN		= 64,

	Rttmax		= 50,
};

struct Req
{
	int	seq;	// sequence number
	vlong	time;	// time sent
	int	rtt;
	Req	 *next;
};

struct Machine
{
	Lock;
	char	*name;
	int	pingfd;
	int	nproc;

	int	rttmsgs;
	ulong	rttsum;
	ulong	lastrtt;

	int	lostmsgs;
	int	rcvdmsgs;
	ulong	lostavg;
	int	unreachable;

	ushort	seq;
	Req	*first;
	Req	*last;
	Req	*rcvd;
	
	char	buf[1024];
	char	*bufp;
	char	*ebufp;
};

enum
{
	Ncolor		= 6,
	Ysqueeze	= 2,	/* vertical squeezing of label text */
	Labspace	= 2,	/* room around label */
	Dot		= 2,	/* height of dot */
	Opwid		= 5,	/* strlen("add  ") or strlen("drop ") */
	NPROC		= 128,
	NMACH		= 32,
};

enum Menu2
{
	Mrtt,
	Mlost,
	Nmenu2,
};

char	*menu2str[Nmenu2+1] = {
	"add  sec rtt",
	"add  % lost ",
	nil,
};


void	rttval(Machine*, long*, long*, long*);
void	lostval(Machine*, long*, long*, long*);

Menu	menu2 = {menu2str, nil};
int		present[Nmenu2];
void		(*newvaluefn[Nmenu2])(Machine*, long*, long*, long*) = {
	rttval,
	lostval,
};

Image		*cols[Ncolor][3];
Graph		*graph;
Machine		mach[NMACH];
Font		*mediumfont;
int		pids[NPROC];
int		npid;
int 		parity;	/* toggled to avoid patterns in textured background */
int		nmach;
int		ngraph;	/* totaly number is ngraph*nmach */
long		starttime;
int		pinginterval;

void	dropgraph(int);
void	addgraph(int);
void	startproc(void (*)(void*), void*);
void	resize(void);
ulong	rttscale(ulong);
int	which2index(int);
int	index2which(int);

void
killall(char *s)
{
	int i, pid;

	pid = getpid();
	for(i=0; i<NPROC; i++)
		if(pids[i] && pids[i]!=pid)
			postnote(PNPROC, pids[i], "kill");
	exits(s);
}

void*
emalloc(ulong sz)
{
	void *v;
	v = malloc(sz);
	if(v == nil) {
		fprint(2, "%s: out of memory allocating %ld: %r\n", argv0, sz);
		killall("mem");
	}
	memset(v, 0, sz);
	return v;
}

void*
erealloc(void *v, ulong sz)
{
	v = realloc(v, sz);
	if(v == nil) {
		fprint(2, "%s: out of memory reallocating %ld: %r\n", argv0, sz);
		killall("mem");
	}
	return v;
}

char*
estrdup(char *s)
{
	char *t;
	if((t = strdup(s)) == nil) {
		fprint(2, "%s: out of memory in strdup(%.10s): %r\n", argv0, s);
		killall("mem");
	}
	return t;
}

void
mkcol(int i, int c0, int c1, int c2)
{
	cols[i][0] = allocimagemix(display, c0, DWhite);
	cols[i][1] = allocimage(display, Rect(0,0,1,1), CMAP8, 1, c1);
	cols[i][2] = allocimage(display, Rect(0,0,1,1), CMAP8, 1, c2);
}

void
colinit(void)
{
	mediumfont = openfont(display, "/lib/font/bit/pelm/latin1.8.font");
	if(mediumfont == nil)
		mediumfont = font;

	/* Peach */
	mkcol(0, 0xFFAAAAFF, 0xFFAAAAFF, 0xBB5D5DFF);
	/* Aqua */
	mkcol(1, DPalebluegreen, DPalegreygreen, DPurpleblue);
	/* Yellow */
	mkcol(2, DPaleyellow, DDarkyellow, DYellowgreen);
	/* Green */
	mkcol(3, DPalegreen, DMedgreen, DDarkgreen);
	/* Blue */
	mkcol(4, 0x00AAFFFF, 0x00AAFFFF, 0x0088CCFF);
	/* Grey */
	cols[5][0] = allocimage(display, Rect(0,0,1,1), CMAP8, 1, 0xEEEEEEFF);
	cols[5][1] = allocimage(display, Rect(0,0,1,1), CMAP8, 1, 0xCCCCCCFF);
	cols[5][2] = allocimage(display, Rect(0,0,1,1), CMAP8, 1, 0x888888FF);
}

int
loadbuf(Machine *m, int *fd)
{
	int n;


	if(*fd < 0)
		return 0;
	seek(*fd, 0, 0);
	n = read(*fd, m->buf, sizeof m->buf);
	if(n <= 0){
		close(*fd);
		*fd = -1;
		return 0;
	}
	m->bufp = m->buf;
	m->ebufp = m->buf+n;
	return 1;
}

void
label(Point p, int dy, char *text)
{
	char *s;
	Rune r[2];
	int w, maxw, maxy;

	p.x += Labspace;
	maxy = p.y+dy;
	maxw = 0;
	r[1] = '\0';
	for(s=text; *s; ){
		if(p.y+mediumfont->height-Ysqueeze > maxy)
			break;
		w = chartorune(r, s);
		s += w;
		w = runestringwidth(mediumfont, r);
		if(w > maxw)
			maxw = w;
		runestring(screen, p, display->black, ZP, mediumfont, r);
		p.y += mediumfont->height-Ysqueeze;
	}
}

void
hashmark(Point p, int dy, int v, int vmax, char *label)
{
	int y;
	int x;

	x = p.x + Labspace;
	y = p.y + (dy*(vmax-v))/vmax;
	draw(screen, Rect(p.x, y-1, p.x+Labspace, y+1), display->black, nil, ZP);
	if(dy > 5*mediumfont->height)
		string(screen, Pt(x, y-mediumfont->height/2),
			display->black, ZP, mediumfont, label);
}

void
hashmarks(Point p, int dy, int which)
{
	switch(index2which(which)){
	case Mrtt:
		hashmark(p, dy, rttscale(1000000), Rttmax, "1.");
		hashmark(p, dy, rttscale(100000), Rttmax, "0.1");
		hashmark(p, dy, rttscale(10000), Rttmax, "0.01");
		hashmark(p, dy, rttscale(1000), Rttmax, "0.001");
		break;
	case Mlost:
		hashmark(p, dy, 75, 100, " 75%");
		hashmark(p, dy, 50, 100, " 50%");
		hashmark(p, dy, 25, 100, " 25%");
		break;
	}
}

Point
paritypt(int x)
{
	return Pt(x+parity, 0);
}

Point
datapoint(Graph *g, int x, long v, long vmax)
{
	Point p;

	p.x = x;
	p.y = g->r.max.y - Dy(g->r)*v/vmax - Dot;
	if(p.y < g->r.min.y)
		p.y = g->r.min.y;
	if(p.y > g->r.max.y-Dot)
		p.y = g->r.max.y-Dot;
	return p;
}

void
drawdatum(Graph *g, int x, long prev, long v, long vmax)
{
	int c;
	Point p, q;

	c = g->colindex;
	p = datapoint(g, x, v, vmax);
	q = datapoint(g, x, prev, vmax);
	if(p.y < q.y){
		draw(screen, Rect(p.x, g->r.min.y, p.x+1, p.y), cols[c][0], nil, paritypt(p.x));
		draw(screen, Rect(p.x, p.y, p.x+1, q.y+Dot), cols[c][2], nil, ZP);
		draw(screen, Rect(p.x, q.y+Dot, p.x+1, g->r.max.y), cols[c][1], nil, ZP);
	}else{
		draw(screen, Rect(p.x, g->r.min.y, p.x+1, q.y), cols[c][0], nil, paritypt(p.x));
		draw(screen, Rect(p.x, q.y, p.x+1, p.y+Dot), cols[c][2], nil, ZP);
		draw(screen, Rect(p.x, p.y+Dot, p.x+1, g->r.max.y), cols[c][1], nil, ZP);
	}
	g->vmax = vmax;
}

void
drawmark(Graph *g, int x)
{
	int c;

	c = (g->colindex+1)&Ncolor;
	draw(screen, Rect(x, g->r.min.y, x+1, g->r.max.y), cols[c][2], nil, ZP);
}

void
redraw(Graph *g, int vmax)
{
	int i, c;

	c = g->colindex;
	draw(screen, g->r, cols[c][0], nil, paritypt(g->r.min.x));
	for(i=1; i<Dx(g->r); i++)
		drawdatum(g, g->r.max.x-i, g->data[i-1], g->data[i], vmax);
	drawdatum(g, g->r.min.x, g->data[i], g->data[i], vmax);
}

void
clearmsg(Graph *g)
{
	if(g->overtmp != nil)
		draw(screen, g->overtmp->r, g->overtmp, nil, g->overtmp->r.min);
	g->overflow = 0;
}

void
drawmsg(Graph *g, char *msg)
{
	if(g->overtmp == nil)
		return;

	// save previous contents of screen
	draw(g->overtmp, g->overtmp->r, screen, nil, g->overtmp->r.min);

	// draw message
	if(strlen(msg) > g->overtmplen)
		msg[g->overtmplen] = 0;
	string(screen, g->overtmp->r.min, display->black, ZP, mediumfont, msg);
}

void
clearcursor(Graph *g)
{
	int x;
	long prev;

	if(g->overtmp == nil)
		return;

	if(g->cursor > 0 && g->cursor < g->ndata){
		x = g->r.max.x - g->cursor;
		prev = 0;
		if(g->cursor > 0)
			prev = g->data[g->cursor-1];
		drawdatum(g, x, prev, g->data[g->cursor], g->vmax);
		g->cursor = -1;
	}
}

void
drawcursor(Graph *g, int x)
{
	if(g->overtmp == nil)
		return;

	draw(screen, Rect(x, g->r.min.y, x+1, g->r.max.y), cols[g->colindex][2], nil, ZP);
}

void
update1(Graph *g, long v, long vmax, long mark)
{
	char buf[Gmsglen];

	// put back screen value sans message
	if(g->overflow || *g->msg){
		clearmsg(g);
		g->overflow = 0;
	}

	draw(screen, g->r, screen, nil, Pt(g->r.min.x+1, g->r.min.y));
	drawdatum(g, g->r.max.x-1, g->data[0], v, vmax);
	if(mark)
		drawmark(g, g->r.max.x-1);
	memmove(g->data+1, g->data, (g->ndata-1)*sizeof(g->data[0]));
	g->data[0] = v;
	if(v>vmax){
		g->overflow = 1;
		sprint(buf, "%ld", v);
		drawmsg(g, buf);
	} else if(*g->msg)
		drawmsg(g, g->msg);

	if(g->cursor >= 0){
		g->cursor++;
		if(g->cursor >= g->ndata){
			g->cursor = -1;
			if(*g->msg){
				clearmsg(g);
				*g->msg = 0;
			}
		}
	}
	
}

void
pinglost(Machine *m, Req*)
{
	m->lostmsgs++;
}

void
pingreply(Machine *m, Req *r)
{
	ulong x;

	x = r->time/1000LL;
	m->rttsum += x;
	m->rcvdmsgs++;
	m->rttmsgs++;
}


void
pingclean(Machine *m, ushort seq, vlong now, int)
{
	Req **l, *r;
	vlong x, y;

	y = 10LL*1000000000LL;
	for(l = &m->first; *l; ){
		r = *l;
		x = now - r->time;
		if(x > y || r->seq == seq){
			*l = r->next;
			r->time = x;
			if(r->seq != seq)
				pinglost(m, r);
			else
				pingreply(m, r);
			free(r);
		} else
			l = &(r->next);
	}
}

void
pingsend(Machine *m)
{
	char buf[128];
	Icmp *ip;
	int i;
	Req *r;
	char err[ERRMAX];

	ip = (Icmp*)buf;

	r = malloc(sizeof *r);
	if(r == nil)
		return;

	for(i = 32; i < 64; i++)
		buf[i] = i;
	ip->type = EchoRequest;
	ip->code = 0;
	ip->seq[0] = m->seq;
	ip->seq[1] = m->seq>>8;
	r->seq = m->seq;
	r->next = nil;
	lock(m);
	pingclean(m, -1, nsec(), 0);
	if(m->first == nil)
		m->first = r;
	else
		m->last->next = r;
	m->last = r;
	r->time = nsec();
	unlock(m);
	if(write(m->pingfd, ip, MSGLEN) < MSGLEN){
		errstr(err, sizeof err);
		if(strstr(err, "unreach")||strstr(err, "exceed"))