exercise 7 - packet transmission from kernel or user space

inc/error.h

@@ -25,6 +25,7 @@ enum {
 	E_FILE_EXISTS	,	// File already exists
 	E_NOT_EXEC	,	// File not a valid executable
 	E_NOT_SUPP	,	// Operation not supported
+	E_ETH_OVF	,	// Ethernet buffer is full
 
 	MAXERROR
 };

inc/lib.h

@@ -59,6 +59,7 @@ int	sys_page_map(envid_t src_env, void *src_pg,
 int	sys_page_unmap(envid_t env, void *pg);
 int	sys_ipc_try_send(envid_t to_env, uint32_t value, void *pg, int perm);
 int	sys_ipc_recv(void *rcv_pg);
+int sys_send_packet(void *buffer, size_t length); 
 unsigned int sys_time_msec(void);
 
 // This must be inlined.  Exercise for reader: why?

inc/syscall.h

@@ -18,6 +18,8 @@ enum {
 	SYS_ipc_try_send,
 	SYS_ipc_recv,
 	SYS_time_msec,
+	SYS_send_packet,
+	SYS_receive_packet,
 	NSYSCALLS
 };
 

kern/Makefrag

@@ -90,6 +90,7 @@ KERN_BINFILES +=	user/testfile \
 
 # Binary files for LAB6
 KERN_BINFILES +=	user/testtime \
+            user/testethsend\
 			user/httpd \
 			user/echosrv \
 			user/echotest \

kern/e1000.c

@@ -1,5 +1,6 @@
 #include <kern/e1000.h>
 #include <kern/pmap.h>
+#include <inc/string.h>
 
 volatile uint32_t *e1000;
 
@@ -8,7 +9,11 @@ volatile uint32_t *e1000;
 uint8_t send_buffer[TDLEN][MTU];
 // align this on 16-bytes boundary
 
-struct tx_desc descs[TDLEN];
+struct tx_desc descs[TDLEN] = { {0} };
+
+
+static int cur = 0;
+
 
 int e1000_attach_fn(struct pci_func *pcif) {
 	pci_func_enable(pcif);
@@ -28,6 +33,44 @@ int e1000_attach_fn(struct pci_func *pcif) {
 	e1000[E1000_TIPG] = 10 << E1000_IGPT_SHIFT | 10 << E1000_IGPR1_SHIFT 
 	| 10 << E1000_IGPR2_SHIFT; // TODO revoir totalement ça ! 10.4.34
 
+
+	int i = 0;
+	for (i = 0; i < TDLEN; i++) {
+		// has to be set the first time we use a descriptor
+		// we use this bit to make sure a descriptor is available
+		// set by the hardware after the first use
+		descs[i].status = E1000_TXD_STAT_DD;
+	}
+
 	// TODO que renvoyer ?
 	return 0;
 }
+
+int e1000_send_packet(void *buffer, size_t length) {
+	assert(length <= MTU);
+
+	if (!(descs[cur].status & E1000_TXD_STAT_DD)) {
+		cprintf("can't reuse %d\n", cur);
+		return -1;
+	}	
+
+	memset(&descs[cur], 0, sizeof(struct tx_desc));
+	memcpy(send_buffer[cur], buffer, length);
+
+	descs[cur].addr = (uint64_t) PADDR(send_buffer[cur]);
+	descs[cur].length = (uint32_t) length;
+
+	// set RS bit to know when descriptor has been used and can be recycled
+	// (DD bit is set when that happens)
+	uint8_t cmd = E1000_TXD_CMD_RS | E1000_TXD_CMD_EOP;
+	descs[cur].cmd = cmd; 
+
+	cur = (cur + 1) % TDLEN;
+	e1000[E1000_TDT] = cur;
+
+	return 0;	
+}
+
+
+
+

kern/e1000.h

@@ -50,7 +50,10 @@
 #define E1000_IGPT_SHIFT 0
 #define E1000_IGPR1_SHIFT 10 
 #define E1000_IGPR2_SHIFT 20 
-
+
+#define E1000_TXD_CMD_RS      0x08 /* Report Status */
+#define E1000_TXD_CMD_EOP     0x01 /* Report Status */
+#define E1000_TXD_STAT_DD    0x01 /* Descriptor Done */
 #define MTU 1518
 
 struct tx_desc
@@ -66,4 +69,6 @@ struct tx_desc
 
 int e1000_attach_fn(struct pci_func *pcif);
 
+int e1000_send_packet(void *buffer, size_t length);
+
 #endif	// JOS_KERN_E1000_H

kern/syscall.c

@@ -12,6 +12,7 @@
 #include <kern/console.h>
 #include <kern/sched.h>
 #include <kern/time.h>
+#include <kern/e1000.h>
 
 // Print a string to the system console.
 // The string is exactly 'len' characters long.
@@ -301,6 +302,9 @@ sys_page_map(envid_t srcenvid, void *srcva,
    if ((err = page_insert(dstenv->env_pgdir, p, dstva, perm))) {
            return err;
    }
+
+
+   // TODO utiliser user_mem_check ?
    return 0;
 }
 
@@ -466,6 +470,31 @@ sys_time_msec(void)
   return time_msec();
 }
 
+
+// return 0 on success.
+// Return < 0 on error.  Errors are:
+//  -E_INVAL if buffer isn't readable in user space 
+//  -E_INVAL if len > MTU 
+static int
+sys_send_packet(void *buffer, size_t length) {
+
+  if (length > MTU) {
+    return -E_INVAL;
+  }
+  int r = user_mem_check(curenv, buffer, length, 0);
+  if (r) {
+    return -E_INVAL;
+  }
+
+  r = e1000_send_packet(buffer, length);
+  if (r == -1) {
+     r = -E_ETH_OVF;
+  }
+
+  return r;
+}
+
+
 // Dispatches to the correct kernel function, passing the arguments.
 int32_t
 syscall(uint32_t syscallno, uint32_t a1, uint32_t a2, uint32_t a3, uint32_t a4, uint32_t a5)
@@ -524,6 +553,9 @@ syscall(uint32_t syscallno, uint32_t a1, uint32_t a2, uint32_t a3, uint32_t a4,
         case SYS_time_msec:
            res = sys_time_msec();
            break;
+        case SYS_send_packet:
+           res = sys_send_packet((void *) a1, (int) a2);
+           break;
         case NSYSCALLS:
         default:
            res = -E_INVAL;

lib/syscall.c

@@ -125,3 +125,8 @@ sys_time_msec(void)
 {
 	return (unsigned int) syscall(SYS_time_msec, 0, 0, 0, 0, 0, 0);
 }
+
+int
+sys_send_packet(void *buffer, size_t length) {
+	return syscall(SYS_send_packet, 0, (uint32_t) buffer, (uint32_t) length, 0, 0, 0);
+}

user/testethsend.c

@@ -0,0 +1,20 @@
+#include <inc/lib.h>
+
+#define N 50 
+#define MAX_LEN 100 
+
+char buffer[N][MAX_LEN];
+
+void
+umain(int argc, char **argv)
+{
+	int i = 0;
+
+	for (i = 0; i < N; i++) {
+		snprintf(buffer[i], MAX_LEN, "hello %d\n", i);
+	}
+
+	for (i = 0; i < N; i++) {
+		sys_send_packet(buffer[i], strlen(buffer[i]));
+	}
+}