net add missing files

2 files changed, 349 insertions, 0 deletions

diff --git a/user/nettests.c b/user/nettests.c
new file mode 100644
index 0000000..2f7d6cd
--- /dev/null
+++ b/user/nettests.c
@@ -0,0 +1,297 @@
+#include "kernel/types.h"
+#include "kernel/net.h"
+#include "kernel/stat.h"
+#include "user/user.h"
+
+//
+// send a UDP packet to the localhost (outside of qemu),
+// and receive a response.
+//
+static void
+ping(uint16 sport, uint16 dport, int attempts)
+{
+  int fd;
+  char *obuf = "a message from xv6!";
+  uint32 dst;
+
+  // 10.0.2.2, which qemu remaps to the external host,
+  // i.e. the machine you're running qemu on.
+  dst = (10 << 24) | (0 << 16) | (2 << 8) | (2 << 0);
+
+  // you can send a UDP packet to any Internet address
+  // by using a different dst.
+  
+  if((fd = connect(dst, sport, dport)) < 0){
+    fprintf(2, "ping: connect() failed\n");
+    exit(1);
+  }
+
+  for(int i = 0; i < attempts; i++) {
+    if(write(fd, obuf, strlen(obuf)) < 0){
+      fprintf(2, "ping: send() failed\n");
+      exit(1);
+    }
+  }
+
+  char ibuf[128];
+  int cc = read(fd, ibuf, sizeof(ibuf)-1);
+  if(cc < 0){
+    fprintf(2, "ping: recv() failed\n");
+    exit(1);
+  }
+
+  close(fd);
+  ibuf[cc] = '\0';
+  if(strcmp(ibuf, "this is the host!") != 0){
+    fprintf(2, "ping didn't receive correct payload\n");
+    exit(1);
+  }
+}
+
+// Encode a DNS name
+static void
+encode_qname(char *qn, char *host)
+{
+  char *l = host; 
+  
+  for(char *c = host; c < host+strlen(host)+1; c++) {
+    if(*c == '.') {
+      *qn++ = (char) (c-l);
+      for(char *d = l; d < c; d++) {
+        *qn++ = *d;
+      }
+      l = c+1; // skip .
+    }
+  }
+  *qn = '\0';
+}
+
+// Decode a DNS name
+static void
+decode_qname(char *qn, int max)
+{
+  char *qnMax = qn + max;
+  while(1){
+    if(qn >= qnMax){
+      printf("invalid DNS reply\n");
+      exit(1);
+    }
+    int l = *qn;
+    if(l == 0)
+      break;
+    for(int i = 0; i < l; i++) {
+      *qn = *(qn+1);
+      qn++;
+    }
+    *qn++ = '.';
+  }
+}
+
+// Make a DNS request
+static int
+dns_req(uint8 *obuf)
+{
+  int len = 0;
+  
+  struct dns *hdr = (struct dns *) obuf;
+  hdr->id = htons(6828);
+  hdr->rd = 1;
+  hdr->qdcount = htons(1);
+  
+  len += sizeof(struct dns);
+  
+  // qname part of question
+  char *qname = (char *) (obuf + sizeof(struct dns));
+  char *s = "pdos.csail.mit.edu.";
+  encode_qname(qname, s);
+  len += strlen(qname) + 1;
+
+  // constants part of question
+  struct dns_question *h = (struct dns_question *) (qname+strlen(qname)+1);
+  h->qtype = htons(0x1);
+  h->qclass = htons(0x1);
+
+  len += sizeof(struct dns_question);
+  return len;
+}
+
+// Process DNS response
+static void
+dns_rep(uint8 *ibuf, int cc)
+{
+  struct dns *hdr = (struct dns *) ibuf;
+  int len;
+  char *qname = 0;
+  int record = 0;
+
+  if(cc < sizeof(struct dns)){
+    printf("DNS reply too short\n");
+    exit(1);
+  }
+
+  if(!hdr->qr) {
+    printf("Not a DNS reply for %d\n", ntohs(hdr->id));
+    exit(1);
+  }
+
+  if(hdr->id != htons(6828)){
+    printf("DNS wrong id: %d\n", ntohs(hdr->id));
+    exit(1);
+  }
+  
+  if(hdr->rcode != 0) {
+    printf("DNS rcode error: %x\n", hdr->rcode);
+    exit(1);
+  }
+  
+  //printf("qdcount: %x\n", ntohs(hdr->qdcount));
+  //printf("ancount: %x\n", ntohs(hdr->ancount));
+  //printf("nscount: %x\n", ntohs(hdr->nscount));
+  //printf("arcount: %x\n", ntohs(hdr->arcount));
+  
+  len = sizeof(struct dns);
+
+  for(int i =0; i < ntohs(hdr->qdcount); i++) {
+    char *qn = (char *) (ibuf+len);
+    qname = qn;
+    decode_qname(qn, cc - len);
+    len += strlen(qn)+1;
+    len += sizeof(struct dns_question);
+  }
+
+  for(int i = 0; i < ntohs(hdr->ancount); i++) {
+    if(len >= cc){
+      printf("invalid DNS reply\n");
+      exit(1);
+    }
+    
+    char *qn = (char *) (ibuf+len);
+
+    if((int) qn[0] > 63) {  // compression?
+      qn = (char *)(ibuf+qn[1]);
+      len += 2;
+    } else {
+      decode_qname(qn, cc - len);
+      len += strlen(qn)+1;
+    }
+      
+    struct dns_data *d = (struct dns_data *) (ibuf+len);
+    len += sizeof(struct dns_data);
+    //printf("type %d ttl %d len %d\n", ntohs(d->type), ntohl(d->ttl), ntohs(d->len));
+    if(ntohs(d->type) == ARECORD && ntohs(d->len) == 4) {
+      record = 1;
+      printf("DNS arecord for %s is ", qname ? qname : "" );
+      uint8 *ip = (ibuf+len);
+      printf("%d.%d.%d.%d\n", ip[0], ip[1], ip[2], ip[3]);
+      if(ip[0] != 128 || ip[1] != 52 || ip[2] != 129 || ip[3] != 126) {
+        printf("wrong ip address");
+        exit(1);
+      }
+      len += 4;
+    }
+  }
+
+  // needed for DNS servers with EDNS support
+  for(int i = 0; i < ntohs(hdr->arcount); i++) {
+    char *qn = (char *) (ibuf+len);
+    if(*qn != 0) {
+      printf("invalid name for EDNS\n");
+      exit(1);
+    }
+    len += 1;
+
+    struct dns_data *d = (struct dns_data *) (ibuf+len);
+    len += sizeof(struct dns_data);
+    if(ntohs(d->type) != 41) {
+      printf("invalid type for EDNS\n");
+      exit(1);
+    }
+    len += ntohs(d->len);
+  }
+
+  if(len != cc) {
+    printf("Processed %d data bytes but received %d\n", len, cc);
+    exit(1);
+  }
+  if(!record) {
+    printf("Didn't receive an arecord\n");
+    exit(1);
+  }
+}
+
+static void
+dns()
+{
+  #define N 1000
+  uint8 obuf[N];
+  uint8 ibuf[N];
+  uint32 dst;
+  int fd;
+  int len;
+
+  memset(obuf, 0, N);
+  memset(ibuf, 0, N);
+  
+  // 8.8.8.8: google's name server
+  dst = (8 << 24) | (8 << 16) | (8 << 8) | (8 << 0);
+
+  if((fd = connect(dst, 10000, 53)) < 0){
+    fprintf(2, "ping: connect() failed\n");
+    exit(1);
+  }
+
+  len = dns_req(obuf);
+  
+  if(write(fd, obuf, len) < 0){
+    fprintf(2, "dns: send() failed\n");
+    exit(1);
+  }
+  int cc = read(fd, ibuf, sizeof(ibuf));
+  if(cc < 0){
+    fprintf(2, "dns: recv() failed\n");
+    exit(1);
+  }
+  dns_rep(ibuf, cc);
+
+  close(fd);
+}  
+
+int
+main(int argc, char *argv[])
+{
+  int i, ret;
+  uint16 dport = NET_TESTS_PORT;
+
+  printf("nettests running on port %d\n", dport);
+  
+  printf("testing ping: ");
+  ping(2000, dport, 1);
+  printf("OK\n");
+  
+  printf("testing single-process pings: ");
+  for (i = 0; i < 100; i++)
+    ping(2000, dport, 1);
+  printf("OK\n");
+  
+  printf("testing multi-process pings: ");
+  for (i = 0; i < 10; i++){
+    int pid = fork();
+    if (pid == 0){
+      ping(2000 + i + 1, dport, 1);
+      exit(0);
+    }
+  }
+  for (i = 0; i < 10; i++){
+    wait(&ret);
+    if (ret != 0)
+      exit(1);
+  }
+  printf("OK\n");
+  
+  printf("testing DNS\n");
+  dns();
+  printf("DNS OK\n");
+  
+  printf("all tests passed.\n");
+  exit(0);
+}
diff --git a/user/pingpong.c b/user/pingpong.c
new file mode 100644
index 0000000..6ed12e7
--- /dev/null
+++ b/user/pingpong.c
@@ -0,0 +1,52 @@
+#include "kernel/types.h"
+#include "kernel/stat.h"
+#include "user/user.h"
+
+#define N 5
+char buf[N];
+
+void
+pong(int *parent_to_child, int *child_to_parent) {
+  if (read(parent_to_child[0], buf, N) < 0) {
+    printf("read failed\n");
+  }
+  printf("%d: received %s\n", getpid(), buf);
+  if (write(child_to_parent[1], "pong", 4) != 4) {
+    printf("write failed\n");
+  }
+}
+
+void
+ping(int *parent_to_child, int *child_to_parent) {
+  
+  if (write(parent_to_child[1], "ping", 4) != 4) {
+    printf("write failed\n");
+  }
+  if (read(child_to_parent[0], buf, N) < 0) {
+    printf("read failed\n");
+  }
+  printf("%d: received %s\n", getpid(), buf);
+}
+
+int
+main(int argc, char *argv[])
+{
+  int parent_to_child[2];
+  int child_to_parent[2];
+
+  int pid;
+
+  if (pipe(parent_to_child) < 0 || pipe(child_to_parent) < 0) {
+    printf("pipe failed\n");
+  }
+  if ((pid = fork()) < 0) {
+    printf("fork failed\n");
+  }
+  if (pid == 0) {
+    pong(parent_to_child, child_to_parent);
+  } else {
+    ping(parent_to_child, child_to_parent);
+  }
+  
+  exit(0);
+}