get a integer from char* ...?

Projects Programming
13

I think it does answer your questions. If you need to know which servo, and it is always the 3rd character, then:

int servoNumber;
int value;
int len;
char msg[7];

servoNumber = msg[2] - '0';   // Servo number
len = udp.read(msg,7);
msg[6] = '\0';
value = atoi(&msg[3]);        // Value from the read